Decelerometer formed by levitating a substrate into equilibrium

ABSTRACT

Coulomb islands are charged to create Coulomb forces which are applied between a first and second substrate. The Coulomb islands are used to levitate the first substrate over the second substrate into an equilibrium position. A processing unit monitors the values of capacitors formed between the substrates to provide feedback information to maintain the first substrate in this equilibrium position. The first substrate can be an accelerometer that can be used to calculate the direction and magnitude of a deceleration. The processing unit sends the digital information to a bus coupled to a plurality of air bags. The digital information identifies the appropriate air bags that need to be enabled to minimize the impact of a crash. Vertical changes in acceleration can also be detected making this invention applicable for flight vehicles.

BACKGROUND OF THE INVENTION

ASIC (Application Specific Integrated Circuit) and custom logictypically are unforgiving systems since an error in the logic may notallow for an easy recovery once the device has been fabricated. There-design cycle time can be 3-4 months. An FPGA (Field Programmable GateArray), however, is an on the fly reconfigurable Boolean logic system.The heart of Reconfigurable logic is the configurable logic block whichis formed using Boolean logic and can be altered very easily since aninput digital signal can modify the operation of the logic block withoutphysically altering it. The ability to program, use, reprogram, use andreprogram, use and continue this cycle infinitum are features verydesirable which allow a system to adapt to different changingspecifications or conditions quickly. The re-design cycle can be done inseconds. This helps explain why the reconfigurable logic business hasgrown into a several billion dollar enterprise.

Reconfigurable systems are very useful and allow for a rapid change tothe system to achieve the desired behavior in a short time period. Thereare situations where some systems that would desire the ability to bereconfigurable but currently are not able to do so. These systemscontain a component that is a discrete element: inductor, capacitor orantenna. It is difficult to replace these discrete elements withswitches formed from active circuitry since the circuitry introducesloss and degrades the characteristics of the discrete elements. An RF(Radio Frequency) switch is used to switch the antenna from thetransmitter to the receiver and the switch itself unfortunatelyintroduces a loss of about 0.5 db. This is because it is difficult toreplace metal with active components. In order to switch in a differentvalue of an inductor, a first switch must disconnect the first inductorand a second switch must connect the new inductor. However, the switchintroduces a loss and reduces the Q of the inductor; this is typicallyan undesirable effect. Finally, variable capacitors are currently formedby active devices; diodes or MOS gates, etc. These capacitors can behavenonlinearly and have a limited range of linear operation over a givenvoltage range.

In addition, wireless systems are comprised of hardware such astransmitters, receivers, DSPs (Digital Signal Processor), memory, D/A(Digital to Analog), A/D, filters and antennas. Typically, the wirelesscommunication channel in a system may operate in a new frequency band.However, the system would perform better if the passive components couldbe changed to operate at that new frequency band. Since the hardware isphysically soldered and bound in place in the system, it is verydifficult to replace them with hardware that has been optimized tooperate at this newer frequency band. One approach to this problem is todesign the hardware so it operates over a larger frequency band. Theconsequences are a loss in gain and not being able to achieve theultimate performance with an optimum design.

It would be very desirable to have a system that can be physicallyreconfigured to adapt to a changing conditions. For example, it would bedesirable to have an inductor, antenna, capacitor or other hardwarecomponents to be physically alterable after they have been placed in thesystem. This specification addresses these concerns as described in thefollowing section.

BRIEF SUMMARY OF THE INVENTION

One embodiment is dropping droplets of fluids onto substrates, formingvarious contact angles, overhanging the droplets over the edge of thesubstrate and moving two substrates until at least one droplet from eachsubstrate make contact. Then, friction can be applied to the commonsurface to understand the properties of the surface tension. Inaddition, potentials can be applied across the membrane to study thediffusion properties and the concentration levels can be adjusted withinthe droplet to determine its effect. Another embodiment is forming a LOG(Lab on a Chip) where biological fluids and samples can be pumped,mixed, analyzed and confined into cavities. One embodiment of usingCoulomb forces is to adjust and align laser from/into optical fiber's.Another embodiment allows a pattern of non-overlapping metallic sheetsto determine the acceleration of the system. As the acceleration causesthe distances between the metallic sheets to vary, the amount ofacceleration can be determined. An orthogonal placed pattern of sheetscan be used to determine the direction of the acceleration. Such adevice can be used to enable air bags during a car crash.

Another embodiment is described which uses Coulomb forces to adjust thephysical dimensions of antennas. Thus, antennas can be adjusted in thefield to better match the carrier frequency. Several antennas: the Yagi,the patch, the bow-tie, the meanderline, and the dipole antenna can beadjusted to benefit from this adjustment. As more antennas can be placedon a substrate, additional flexibility occurs such as using an antennaat a given carrier frequency to transmit a signal while the secondantenna can be used to receive the signal at a different carrierfrequency. Conversely, the antennas can be used in a MIMO system toprovide a multi-channel wireless communication where the antennas can bemoved on the surface of a substrate to improve reception. One embodimentis the ability to rotate an antenna substrate 90° around the edge of asubstrate. This allows antennas to be formed that exist in threeorthogonal planes. Receiving and transmitting signals in threeorthogonal dimensions improves reception if one of the signals fades ina given dimension. Many of these techniques are also applicable toinductor construction.

Another embodiment is described that can assemble substrates over oneanother to form a stacked substrate. The various layers of the stackedsubstrate can be separated from each other by using Coulomb forces. Oneembodiment shows how a beam substrate can be used to increase theseparation. The instructions for assembly and a FSM (Finite StateMachine) can be included in the stacked substrate to pave the way for aself-constructing 3-D automaton. The beam substrate can be used to carryheat, fluids, electrical power or signals between the various layers ofthe stacked cells besides providing a mechanical support. The embodimentof a stacked substrate can be assembled into a cylindrical coil, atransformer or a coupled transformer depending on the construction ofthe beam structure. In one embodiment, the magnetic coupling of thetransformer can be altered by changing the distance between theseparated substrates.

In another embodiment, metallic plates can be positioned over oneanother to form capacitor which can be used to detect motion, distance,velocity, position and identity of the substrates. These capacitors canbe used to form an LC tank circuit where the distance between the platesof the capacitor can be altered to alter so that the capacitance isaltered and the frequency is changed. The capacitor can be used tocommunicate digital information between the substrates.

In another embodiment, a combination of attractive and repulsive Coulombforces can be used to form a levitation system using at least twosubstrates. Another is to have two outer substrates that make a channelregion and confine a third substrate within the channel region. Thesystem can be levitated just by using only like charges. In order tointroduce further control, some of the islands can be altered in thestrength and polarity of their charge to move the third substratevertically within the channel region.

Another embodiment is increasing the number of Coulomb islands todecrease the required voltage that needs to be applied to the island.This helps in reducing the stress applied to the junctions and devices.

In another embodiment, the substrate can be processed to exposedmetallic posts or electrical contacts that can provide a DC connectionto provide power and DC signals. In addition the edge can be etched toexpose the metal layers in a substrate to allow an electrical connectionto occur.

In one embodiment of the invention is a system where the substrates canbe reconfigured by the application of adjustable Coulomb forces betweenjuxtaposed surfaces of substrates to create new systems. These forcescan be used to detach, raise, move, rotate, drop and reattach substratesinto new system configurations. An embodiment of placing a pattern ofislands on each juxtaposed substrate and determining the sequence andcharging to lift, move and dropping a substrate. The determination isdone by a control unit that can be confined to one of the substrates,distributed among several substrates, calculated on the fly, stored inmemory, or calculated externally. Feedback from the sensors can be usedto control and stabilize the movement of the substrate. The mastercontrol can be in the mother substrate.

In another embodiment, a Faraday shield can be placed under the Coulombisland to isolate the Coulomb island from the remainder of thesubstrate. In addition, the potential of the Faraday shield can bealtered to control the electric field leaving the substrate and therebycontrolling the force being applied to a juxtaposed Coulomb island.Another embodiment is performing edge processing of a substrate.Vertical Coulomb islands and vertical Faraday shields can be formed.This inventive aspect allows Coulomb islands to be charged to attracttwo or more substrates along their edge.

In another embodiment, charge is induced in a metallic Coulomb island byan externally charged plate. The Coulomb island can have a probe openingto directly charge the island, and then this charged Coulomb island canbe used to induce a charge on another Coulomb island. The probe openingcan be mechanically probed using an external probe or a MEMS probe. Inanother embodiment, the gate of a non-volatile memory that is isolatedis connected to a Coulomb island where the entire combined structure issurrounded by an insulator. The island is placed at the surface of thesubstrate to maximize the forces that can be generated between thisisland and another island located near the surface of a secondsubstrate. Furthermore, several non-volatile devices can be connected tothe island simultaneously where each device can be optimized to performa special function.

In another embodiment, Coulomb forces are used to detach substrates fromthe system to decrease leakage current in that substrate to decreasepower dissipation. An embodiment allows an inductor on a substrate to belevitated so that losses of the inductor are decreased. Anotherembodiment is wire bonding a substrate to power and DC supplies andusing the Coulomb force to lift the substrate so that the substrate islevitated. Another embodiment is using the Coulomb forces between twosubstrates to cause one of the substrates to overhang a new substratewhich does not have Coulomb islands. However, the substrate over hangingthe new substrate can electrically connect to the new substrate tointroduce a new circuit element into the new substrate.

BRIEF DESCRIPTION OF THE DRAWINGS

Please note that the drawings shown in this specification may not bedrawn to scale and the relative dimensions of various elements in thediagrams are depicted schematically and not to scale.

FIGS. 1 a-1 h depict a reconfigurable system in accordance with thepresent invention.

FIG. 1 i) illustrates a side cross-sectional view of the reconfigurablesystem with the daughter substrates connected and j) levitated to themother substrate in accordance with the present invention.

FIG. 1 k shows a flowchart to reconfigurable the system in accordancewith the present invention (Note that the decision unit has a blockshape instead of a diamond one).

FIG. 2 a depict the diagram used to calculate the force of a chargeddisk in accordance with the present invention.

FIG. 2 b illustrates two charged islands juxtaposed to each other inaccordance with the present invention.

FIG. 2 c) reveals plot of gravitational force of substrates and thevoltage necessary to apply to an island pair, d) a plot of the voltageapplied to the islands to maintain a constant force as a function of thenumber of islands, and d(1)) the forces between a sphere and a plane inaccordance with the present invention.

FIG. 2 e) presents a portion of a unit component from a reconfigurablesystem with a surface charge and f-g) depict a portion of a unit,component from a reconfigurable system with an electric field inaccordance with the present invention.

FIG. 3 a illustrates a chargeable plate in a reconfigurable system inaccordance with the present invention.

FIG. 3 b reveals forming an induced charge on a chargeable plate in areconfigurable system in accordance with the present invention.

FIG. 3 c shows the cross sectional view of a probe (could be external oron-substrate) routing excess negative charge to a power supply in areconfigurable system in accordance with the present invention.

FIG. 3 d presents the probe being disconnected in a reconfigurablesystem in accordance with the present invention.

FIG. 3 e depicts the cross sectional view of the electric field from thechargeable plate in a reconfigurable system in accordance with thepresent invention.

FIG. 3 f illustrates the top view of the chargeable plate in areconfigurable system in accordance with the present invention.

FIGS. 4 a and 4 c reveal the cross sectional view of the electric fieldof the chargeable plate after placing a second chargeable plate (forminga Faraday Shield) beneath the initial chargeable plate in areconfigurable system in accordance with the present invention.

FIGS. 4 b and 4 d show the top view of the chargeable plate in areconfigurable system in accordance with the present invention.

FIG. 5 a) presents the cross sectional view of the Faraday Shield, b)depicts the cross sectional view of a negatively charged plate causingan induced charge to form on a second chargeable plate in areconfigurable system, c) illustrates a negative probe canceling theexcess positive charge of the second chargeable plate of the crosssectional view of the Faraday Shield, d) reveals a negative charge onthe second plate, e) the island set to a negative potential and f) theshield set to a negative potential in accordance with the presentinvention.

FIG. 6 a) illustrates a cross sectional view and b) reveals the top viewof the FAMOS device illustrating the source, drain, gate and contactwindow.

FIG. 6 c shows the 2-D with perspective of a chargeable plate connectedby metallic stacks to the gate of the FAMOS device in accordance withthe present invention.

FIG. 6 d) presents the cross sectional view 6-22 of FIG. 6 c and e)reveals a Faraday Shield formed beneath the chargeable plate inaccordance with the present invention.

FIG. 7 a) illustrates a cross sectional view and b) reveals the top viewof the SAMOS device illustrating the source, drain, gates and contactwindow.

FIG. 7 c) presents the cross sectional view of a chargeable plateconnected by a metallic stack to the gate of the SAMOS device, d)reveals a Faraday Shield formed beneath the chargeable plate, e) showsthe chargeable plate having a positive charge formed either by inducedcharging or probing and f) presents a voltage adjustable Faraday Shieldbeneath the chargeable plate in accordance with the present invention.

FIG. 8 a) depicts two substrates preparing to be bonded together whereone substrate has been given a charge and b) illustrates the chargedbonded substrate of FIG. 8 a.

FIG. 9 a) reveals a positive charged substrate held by an attractiveCoulomb force to the negative charged substrate and b) shows therepulsive Coulomb force between two similarly charged substrates inaccordance with the present invention.

FIG. 10 a) presents repulsive/attractive charged substrates that areheld apart by a repelling Coulomb Force and b) depicts therepulsive/attractive charged substrates (one with less positive charge)causing more separation due to a less attracting Coulomb force inaccordance with the present invention.

FIG. 11 a) illustrates a region bounded by negative charged substrateswhere a central wafer bonded substrate levitates within the channelregion due to the repelling Coulomb force, b) reveals a second centralwafer bonded substrate in a channel and c) presents yet a thirdembodiment of the central wafer bonded substrate in a channel inaccordance with the present invention.

FIG. 12 a) depicts two face-to-face positively charged substrates eachhaving posts, b) illustrates the two face-to-face oppositely chargedsubstrates held together by an attractive Coulomb Force, c) reveals aclose up of the connected post elements and d) shows yet a further closeup of the connected post elements showing the landing areas inaccordance with the present invention.

FIG. 12 e) depicts two face-to-face positively charged substrates eachhaving a moveable contact post, f) illustrates the two face-to-faceoppositely charged substrates held together by an attractive Coulombforce, g) reveals a close up of the un-connected post elements and h)shows a close up of the post elements when connected in accordance withthe present invention.

FIG. 12 i) presents substrates each having punch-through substrate vias,j) depicts the substrates connected by a solder bump, k) illustrates aclose up of the solder bump and l) reveals yet a further close up of thesolder bump illustrating the dam structure in accordance with thepresent invention.

FIG. 13 a) shows a packaged system incorporating a levitating Coulombforce device and b) presents a packaged system incorporating alevitating Coulomb force device extracting energy from a magnetic fieldin accordance with the present invention.

FIG. 14 depicts a packaged system incorporating a levitating Coulombforce device that contains a portion a) of a capacitor and c) a secondversion of a capacitor in accordance with the present invention.

FIG. 14 illustrates the schematic diagram showing b) the adjustablecapacitor and d) a pair of adjustable capacitors in a packaged systemincorporating a levitating Coulomb force device in accordance with thepresent invention.

FIG. 15 a presents a packaged system incorporating a levitating Coulombforce device containing an inductor, b) depicts a physical layout of aninductor coil and e) illustrates the schematic of the inductor inaccordance with the present invention.

FIG. 16 reveals a packaged system incorporating a) a Coulomb forcedevice that contains an inductor and is wire bonded to the lowersubstrate and b) a levitating Coulomb force device which is attached tothe bond wire providing an electrical connection to the upper substratein accordance with the present invention.

FIG. 17 a) presents Coulomb islands that are oppositely charged on twojuxtaposed substrates causing them to be held together by an attractiveCoulomb force and b) depicts the pre-stage charging of islands and thenunit vector forces in preparation for moving the top substrate inaccordance with the present invention.

FIG. 17 c) illustrates the first post-stage charging of islands andtheir unit vector forces to move the top substrate upward and d)illustrates the first post-stage charging of islands and their unitvector forces as the top substrate moves right in the direction ofminimum energy in accordance with the present invention.

FIG. 17 e reveals the second post-stage charging of islands and theirunit vector forces to move the top substrate further to the right, f)shows the third post-stage charging of islands and their unit vectorforces to position the top substrate to contact the mother substrate andg) presents the timing waveforms of the charges applied to the islandsin accordance with the present invention.

FIG. 18 a) depicts the post-stage charging of islands and their unitvector forces to move the levitating substrate vertically and b)illustrates a second post-stage charging of islands and their unitvector forces to move the levitating substrate vertically in accordancewith the present invention.

FIG. 19 a) reveals a 3-D substrate containing 4 Coulomb islands and b)shows the 3-D substrate containing the 4 Coulomb islands (structuraloutline hidden) superimposed over the mother substrate indicating theunit vectors of force applied to the 4 Coulomb islands in accordancewith the present invention.

FIG. 20 a) presents single symbols indicating the condition of thecharge of the islands, b) depicts the combined symbols created byoverlapping the single symbols and c) illustrates several cases ofoverlapping the single symbols to form the combined symbols inaccordance with the present invention.

FIG. 20 d) reveals the 2-D surface view of the mother substratecontaining a matrix of islands where the islands located at (2, 1), (5,1), (2, 4) and (5, 4) are charged positive and e) shows the 2-Dstructural view of the daughter substrate containing the 4 Coulombislands which are negatively charged in accordance with the presentinvention.

FIG. 21 a) presents the superposition of the daughter substrate placedover the mother substrate illustrating the combined symbols as definedin FIG. 20 c where the four islands on the mother substrate are chargedpositively, b) depicts the charging of addition islands on the mothersubstrate in preparation to move the daughter substrate vertically, c)illustrates reversal of charge placed on the islands located at (2, 1),(5, 1), (2, 4) and (5, 4) to levitate and move the daughter substratethrough the potential gradient formed in FIGS. 21 b and d) reveals thatthe daughter substrate has moved one division upwards in accordance withthe present invention.

FIG. 22 a) shows the 2-D structural view of a daughter substratecontaining the four negatively charged corner Coulomb islands and twointernal islands charged positively, b) presents the superposition ofthe daughter substrate placed over a mother substrate illustrating thecombined symbols as defined in FIG. 20 c where the four outer islands onthe mother substrate are charged positive, c) depicts the charging ofaddition islands on the mother substrate in preparation to rotate thedaughter substrate, d) illustrates reversal of charge placed on theislands located at (2, 2), (5, 2), (2, 5) and (5, 5) to levitate androtate the daughter substrate through the potential gradient formed inFIGS. 22 b and e) reveals that the daughter has rotated 45° and f)depicts the daughter after a rotation of slightly more than 45° inaccordance with the present invention.

FIG. 22 g) shows that the daughter has rotated another 45° (note thatthe symbols on the daughter substrate have been corrected due to the 90°rotation) and h) presents the daughter substrate attached to the mothersubstrate after being rotate 90° in accordance with the presentinvention.

FIG. 23 a) depicts a reconfigurable system consisting of multipledaughter substrates on a mother substrate to receive and transmit laserradiation, b) illustrates a flowchart to position the receiver to thelaser radiation and c) reveals a flowchart to position the V-Grooveholding fibers to the edge laser in accordance with the presentinvention.

FIG. 24 a) shows a reconfigurable Lab On a Chip (LOG) System consistingof multiple daughter substrates on a mother substrate to receive, mixand analyze biological components, b) defines the contact angle of dropsand c-d) illustrates movements of the daughter substrates with dropshaving large contact angles to make contact with other drops inaccordance with the present invention.

FIG. 24 e) presents a flowchart to position the cavities to receivesamples from a pipette and f) depicts a flowchart to position thecontainers to deposit reagents into carriers to perform operations andanalysis in accordance with the present invention.

FIG. 25 a) illustrates a mother substrate carrying three daughter andtwo granddaughter substrates where one of the granddaughters isrepositioned, b) reveals further repositioning of the granddaughter, c)shows the second granddaughter being repositioned and d) presents thefinal reconfiguration of the second inductor connected to theMicroprocessor in accordance with the present invention.

FIG. 26 a) depicts an accelerometer comprised of a mother and daughtersubstrate having horizontal offset capacitors, b) illustrates an aboveview of the horizontal offset capacitors, c) reveals a displacement ofthe daughter substrate due to a deceleration and d) shows an above viewof the horizontal offset capacitors after the displacement in accordancewith the present invention.

FIG. 27 presents a 2-D surface view of the offset capacitors a) used todetermine movement in the x and y-directions and b) after a decelerationin the −x direction in accordance with the present invention.

FIG. 27 illustrates a 2-D surface view c) of a second embodiment ofoffset capacitors and d) of a third embodiment of offset capacitors inaccordance with the present invention.

FIG. 28 a) shows a block diagram of an automotive safety system using acomputation unit (DSP) to determine which air bags (AB) should beenabled and b) presents a flowchart measuring the capacitance of theoffset capacitors in accordance with the present invention.

FIG. 29 a) depicts a system of daughter and grand daughter substrates,b) shows a side view of the connect substrate bypassing the I/O circuitsand c) presents a capacitor that is fully charged to provide auxiliarypower to a daughter substrate to provide energy to power the Coulombislands in accordance with the present invention.

FIG. 30 a) shows an RF front end connected to a dipole antenna, b)presents the construction of a dipole antenna, c) depicts an RF frontend connected to a dipole antenna for higher frequencies and d)illustrates the construction of a dipole antenna for higher frequenciesin accordance with the present invention.

FIG. 31 a) shows an RF front end connected to a Yagi antenna, b)presents the construction of a Yagi antenna, c) depicts an RF front endconnected to a patch antenna and d) illustrates the construction of apatch antenna for higher frequencies in accordance with the presentinvention.

FIGS. 32 a-b) show the preparation stage of rotating a substrate arounda corner of a second substrate, c) presents the substrate rotated lessthan 90°, d) depicts the substrate rotated 90° and e) illustrates thesubstrate rotated greater than 90° to place substrate on other side ofsecond substrate in accordance with the present invention.

FIG. 33 a) shows cross sectional view of the results of edge processingforming vertical metal sheets, b) presents edge before edge processing,c) depicts the top view of an edge and d) illustrates a side view inaccordance with the present invention.

FIG. 34 shows the a) top view and b) side view of two substratesconnected on their edges in accordance with the present invention.

FIG. 35 a) depicts an RF front end, antenna substrates and othersubstrates on a mother substrate and b) illustrates the finishedconstruction of a 3-dimentional antenna in accordance with the presentinvention.

FIG. 36 illustrates the construction of a 3-dimentional substrate systemin accordance with the present invention.

FIG. 37 depicts a) the preparation, b) the flipping, c) the stacking ofone substrate on another substrate, d) a stacked substrate, e) a firstlevitated substrate, and f) a second levitated substrate in accordancewith the present invention.

FIG. 38 reveals a) a stacked substrate, b) the preparation of flippingsubstrates, c) the substrates flipped into the open cavity, d) firstraised substrate, e) second raised substrate and f) a 3-dimentionalstructure in accordance with the present invention.

FIG. 39 depicts a) a stacked substrate forming an inductor ortransformer, b) the top view of one of the individual substrates, c) theside view of the same substrate, d) series inductor and e) transformerin accordance with the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Several inventions are presented and are described in thisspecification. All the prior art that has been cited fail to show theinventive techniques including, but not limited to: a moving componentthat; 1) can be detached from its surroundings; 2) can contain Coulombislands with opposing charges: 3) can freely move by using Coulombforces formed by Coulomb charges, and; 4) can adjust the charge of theCoulomb islands in both magnitude and polarity.

FIG. 1 a shows a reconfigurable system 1-1 which uses Coulomb force tolevitate and position the upper substrates on the top surface of thelower substrate. The lower substrate will be addressed as the mothersubstrate 1-2 while the upper ones (1-6 through 1-12) will be called thedaughter substrates in several descriptions. The substrates can be adie, comprised of dice (chips), MCM (Multi Chip Modules), MEMS(Micro-Electro-Mechanical Systems), wafer bonded components or any ofthe previous combinations. For instance, a memory substrate (or die) hastwo surfaces (a top and bottom surface) and has four edges, while athird substrate is formed using a wafer bonding process to combine afirst and second substrate that are now physically bonded together asone substrate. The third substrate also has a top and bottom surface andhas four edges. In addition, once the substrates are fabricated, placedin a system, and levitated the substrate is completely isolated from theremaining portions of the system. Note in this case, some of thedaughter substrates can be moved while the mother substrate is rigid orconnected to a reference foundation (not shown). In one case, thedaughter substrate can turn around the edge of the mother substrate andposition itself on the bottom side of the mother substrate. Thesubstrates shown in this description depicts only (hose components thatrelate to the idea being conveyed. However, any circuitry, devices orany other components formed by using the technology that fabricated thesubstrates can also be used to build VLSI systems on that givensubstrate. The mother substrate 1-2 in this case is a DSP core, althoughit could be a processor, microcontroller, memory, FPGA, a portion of aMCM, MEMS, or any structure upon which processing steps can be appliedto form Coulomb islands or metallic sheets within the mother substrate.

The Coulomb islands can be of a variety of shapes; circular, oval,rectangular or polygon. The Coulomb islands can be perforated or have anameba shape, for instance, a Coulomb island can be multi-fingered. Thedaughter substrates are attached and connected to the top surface 1-3 ofthe mother substrate 1-2. The system 1-1 is currently being used tocommunicate using a Standard frequency band within the United States asindicated by the incoming 1-13 and outgoing 1-14 electromagneticradiation carrying voice, data, pictures or video.

While traveling on the road, the user of the system arrives within thedomain of a new base station that uses a different frequency range inanother Standard frequency band for that region. An automatic sensingunit within the communication device or the user's input is used tocommand the system 1-1 to reconfigure itself to operate in thisdifferent band. To operate in this frequency range, it would be requiredto replace the Rec-A 1-9, Tran-A 1-8 and Inductor-A 1-11 which wereoptimum for the prior band with the Rec-B 1-7, Tran-B 1-6 and Inductor-B1-10 that are optimum for the different band. Replacing the currentcomponents with new components offers several advantages at the systemlevel. A few of the advantages are elimination of RF switches whichcause loss, reduction of power dissipation (since only a minimum numberof devices need to be powered), optimum frequency band optimization(since components that target the desired frequency band are used) andimproved quality factor of the inductor. Note that although only oneinput/output wireless path is illustrated on the mother substrate 1-2,more than one input/output paths can be incorporated into the system1-1, for example, MIMO (Multi Input-Multi Output) system.

The sequences of steps are outlined in FIG. 1 b through FIG. 1 g. FIG. 1b shows daughters 1-7 and 1-11 being moved apart, FIG. 1 c showsdaughters 1-6 and 1-10 being moved left, FIG. 1 d shows 1-8 being moveddown, FIG. 1 e shows 1-9 being moved right. FIG. 1 f shows daughters 1-6and 1-9 being moved in opposite directions. FIG. 1 g shows daughters 1-6and 1-7 being moved in a clockwise direction, and FIG. 1 h shows thedaughters 1-6, 1-7 and 1-10 in their final position. Note that thesethree new daughters are placed in the same locations as the previousthree daughters. The positions of the electrical interface are common toall replaceable substrates. Communication is reestablished after thedaughters make electrical contact after the reconfiguration hascompleted.

Several alternatives using reconfiguration are possible. This depends onthe distribution of the communication system between the mother anddaughter substrates. For example, the mother substrate can containbusses which interconnect a portion of the “A” daughters to the “B”daughters and use reassembly-switch substrates that reconfigure theremaining portion of the interconnect between these two sets ofdaughters and the mother substrate. Another case is for the mothersubstrate to contain two communication systems and several sets ofdaughter substrates. One set of daughters substrates can be used tocommunicate on one band while another set of daughter chips are beingreconfigured to be allowed to operate in a different band. Thissituation may occur at the boundary between the two different basestations to insure that a communication channel is not lost.

The control unit to perform this operation may be shared with allsubstrates or the control unit may exist within the mother substrate,within one of the daughter substrates which is not being reconfigured,for example, memory 1-12 or a combination of the two. The control unithas a computation component that determines the current position of thedaughter substrates and calculates the sequence of steps required toreconfigure the daughter substrates to achieve the desiredconfiguration.

Sensors located between substrates are used by the control unit todetermine the identity, location, vertical position, velocity, anddirection of movement of the daughter substrates. One form of thesensors can use capacitive coupling between a levitated daughter chipand the mother substrate to transfer this information. In one case,power does not have to necessarily be dissipated in the daughtersubstrates using the sensors. The sensor signal enters a first plate ofa first capacitor in the mother substrate and is capacitively coupled tothe second plate of a first capacitor located in the daughter substrate.Electrically this signal is coupled to a second plate of a secondcapacitor located in the daughter substrate that in turn is capacitivelycoupled to a first plate of a second capacitor located in the mothersubstrate. A sensing unit on the mother substrate can measure the totalcapacitance of the series connected capacitors. This value can be usedto derive several physical parameters of the system 1-1 as will bedescribed in a later section. Besides the sensor, the parallel plates onthe daughter and mother substrates can be used to form capacitors. Thesecapacitors can also be used to send/receive data, signals, clocks, etc.

The system 1-1 uses sheets of charge to form Coulomb forces. Thesenon-infinite sheets of charge should be isolated from each other by anoxide or dielectric layer. These sheets of charge are also calledCoulomb islands. Then by charging these sheets, the Coulomb force thatforms between the sheets can be used to perform operations. The sheetscan be charged using one of several techniques: 1) being mechanicallyprobed, either using an external probe, such as a testing probe or aMEMS probe; 2) induced charging: 3) F-N (Fowler-Nordheim) tunneling; 4)ion implantation; or 5) by a combination of the previous possibilities.Note that for the first technique, an opening in the oxide layer will berequired to allow the entry of the mechanical probe. This opening shouldbe as small as possible to minimize the exposure of the uncoveredsurface of the element to the outside environment which can make contactwith the surface and alter the amount of stored charge on the element.Otherwise, one of the superior aspects of the Coulomb island is that thecharge can be held indefinitely. So once the insulated metallic elementis charged, the charge remains and the element can be used over and overagain without further dissipation in energy to generate a Coulomb force.For example, the Coulomb force formed between two sheets of charge, oneon the mother and one on the daughter, can be used to levitate thedaughter substrate indefinitely. The metallic element can be a metal,for example, aluminum, copper, gold, or it could be a dopedsemiconductor like polysilicon.

Most of the charged elements described in this specification are planarin nature where the plane can be a small segment or “Coulomb island”several micrometers on a side forming a metallic planar surface. In somecases, electron implantation can be used to blanket the entire backsurface of a wafer with the same charge. The plane in this case would bea large Coulomb island covering the entire backside of the substrate.Note that the charge can be deposited by electron implantation asdescribed in U.S. Pat. Nos. 6,841,917 and 7,217,582. Note that once thischarge is placed into the substrate, they cannot be easily changed.Thus, this charge is typically non adjustable after this processingstep. In this specification, some of the charge elements that will bedescribed will be called Coulomb islands. Some of these Coulomb islandswill have a permanent charge or are charged once, others can be adjustedin magnitude even while the island is performing an operation and iscompletely detached from the mother substrate, some will have sheetsparallel to the surface of the mother substrate, and some with sheetsparallel to the edge of the mother substrate. The Coulomb islands areused to generate Coulomb forces that can be used to move the daughtersubstrates.

A cross sectional view along 1-15 a is given in FIG. 1 i correspondingto the position of the dotted line 1-15 of FIG. 1 h when the daughtersubstrates are physically and electrically connected to the mothersubstrate along the surface indicated by 1-3. Several issues surroundthe details of how this contact is made: 1) an electrical contactestablishes electrical connectivity between the substrates; 2) a secondelectrical contact can also be formed that is capacitive in nature; and3) the Coulomb force is used to make contact. For example, the physicalcontact is made by squeezing the daughter substrates to the mothersubstrate. The squeezing force is created by using the Coulomb forcebetween oppositely charged Coulomb islands. The electrical contactsallow for DC signal (busses, control signals, etc.) and power supplyconnections (VSS, VDD, VREF, etc.). The substrate maintains stabilitywhile the daughter substrates are being levitated or in movement by theuse of sensors and a control unit incorporating feedback as will bedescribed later.

Shown are the daughter substrates from left to right 1-8, 1-9 1-6 and1-12. All are in contact with the mother substrate 1-2. Substrates asdefined in this specification will contain a portion for foundation, aportion for holding some of the components (devices, interconnects, via,oxide layers, etc.) that form the circuits and possibly a portionholding mechanical components (MEMS, MCM). The substrates have twoportions, for example, substrates 1-2 and 1-12 show a foundation portion(1-16 a and 1-16 b) and a component portion (1-18 a and 1-18 b),respectively.

The foundation portion supports the component portion and offers: 1) theability to handle the substrate without fracturing the substrate intopieces during handling; 2) removal of heat; and 3) possibility ofconducting the power supply current (for example, U.S. Pat. No.4,947,228). In some cases, the substrate is abrasively background toreduce the thickness of the substrate, so they; 1) fit into a finalpackaged portable system; 2) improve heat transfer; 3) increaseflexibility; and 4) reducing the height of stacked substrates (forinstance, stacked memory). This foundation portion typically has athickness ranging from ten's of micrometers to 500 micrometers. It canconsist of one or more layers of semiconductor material (silicon, III-V,such as GaAs), an oxide layer (SiO₂ . . . ), or a combination of thetwo. In some cases, the foundation portion could also contain devices(such as devices formed in the semiconductor material), their contacts(source/drain, diffused interconnect, etc.), drilled vias and Coulombislands. One well known substrate is SOI (Silicon On Insulator). Theconventional CMOS (Complementary Metal Oxide Semiconductor) process alsofalls into this category since the CMOS process typically has afoundation and component portions. The silicon substrate could beepitaxial or bulk construction where an epi or a bulk CMOS wafer can bepartitioned to have a foundation portion and a component portion. A fewpossibilities are suggested but are by no way limiting.

The component portion contains the remaining elements that are requiredto provide electrical activity, mechanical motion, and electricalconnectivity to the substrate. The metal interconnect layers in thecomponent portion comprises; their oxide separation layers, vias, plugs,I/O (Input/Output) pads, power busses, electrical contacts, antennas,inductors, Coulomb islands, moveable metallic components (MEMS) andcapacitors. A few of these examples are shown as examples in FIG. 1 iwhich shows the Coulomb islands [see 1-21, 1-22 a, 1-22 b and 1-20]. Aninsulator such as an oxide layer completely surrounds the Coulomb islandto insure its isolation. Once charged, the island can remain chargedindefinitely.

The component portion would be mechanically polished, for instance usingCMP (Chemical-Mechanical Planarization), to planarize the top surface ofthe substrate. After this step, the Coulomb islands which are formed inthe component portion create Coulomb forces between the two surfacesmore uniformly as the daughter substrate moves over the top surface ofthe mother substrate since both surfaces are more planar. In addition,when the Coulomb forces cause the mother and daughter substrates tocontact, the planarization also insures that electrical contact can bemade. FIG. 1 i illustrates the electrical contacts 1-19 a and 1-19 b.These two contacts are exposed at the surface and allow a physicalelectrical connection such as a power or a DC signal. The surface of thecontacts can be co-planar with the surface or may extend above thesurface. Several examples will be given.

The electrical contact is formed between the contacts which protrudeabove the surface of the substrate. This may require another processingstep, for example, removing some of the oxide layer from the top surfaceto expose and form the protrusion of the metal mesa plateau. Also, thepost can possibly be plated with gold (Au) or any other non-tarnishingconductive layer. This would allow the mother substrate post to makeelectrical contact with all daughter metallic pads. This electricalcontact will be made by the Coulomb force created between oppositelycharged Coulomb islands on juxtaposed substrates. The pattern of theelectrical contacts on the daughter substrate that make contact with themother substrate is called the “footprint.” Note that the footprintlocated on the mother substrate is the mirror image of the footprint ofthe mating daughter. Any daughter substrates that can be exchanged needto have at a bare minimum have a portion of a footprint in common. Thecharged Coulomb islands would be positioned below the existing oxidesurface even after the processing step of removing the oxide to createthe metal post.

Another possibility is to use MEMS to form mechanical contacts andextrude the contacts from a cavity formed in the substrate. Thesecontacts would be forced out using the generated Coulomb force betweenCoulomb islands so that electrical contact can be made with a conductiveplate on a juxtaposed substrate.

Additional portions can be combined together by using wafer bonding. Forinstance, the bottom of a first substrate can be wafer bonded to thebottom of a second substrate. This layering sequence would consist ofthe component, foundation, foundation and component portions. The twocomponent portions would contain signals, interconnect and could containthe charged Coulomb islands.

In addition, a charged Coulomb island can be formed on the backside ofthe substrate using electron implantation. Thus, either the foundationportion or the component portion can contain charged Coulomb islands.

FIG. 1 j illustrates the situation where the system 1-23 levitatesseveral of the daughter substrates as the gap 1-24 shows to prepare themfor movement. The Coulomb islands of the daughter substrate were alteredfrom “positive” to “negative” charge. Since the mother and daughtersubstrates now have “like” charges on the Coulomb islands, the daughtersubstrates separate and levitate over the mother substrate. Many detailsof the illustration have been simplified to present one key idea oflevitation disregarding the stability of the levitated substrates whichwill be described later. Note that the separation can be used to detachthe daughter substrates from the power grid network in the mothersubstrate to significantly reduce the leakage current that each of thedaughter substrates would have drawn otherwise. This separation can beperformed to reduce the parasitic power dissipation of the system whenit is in a power down state.

A flowchart 1-25 is depicted in FIG. 1 k that provides the steps toposition the substrates into their new locations. The first step isoccurs at start 1-26, then a question “Are Daughters in correctposition?” 1-27 is performed, if not then the daughter substratesrequired 1-29 and a calculation of movement for all daughters substrates1-30 is performed by a control unit (not shown), then the requireddaughters substrates are raised from the mother substrate 1-31, thesequence of movements are preformed 1-32, and the daughters are droppedor connected to the mother 1-33. Otherwise, the system moves tocommunicate 1-34.

The Coulomb force is used to detach, levitate, move and reattach thedaughter substrates to reconfigure the system. The Coulomb force isformed between at least two charged elements. These elements can consistof charged points, lines, planes, or volume distributions. When theelements are point charges, the following equation holds:

$\begin{matrix}{F = {\frac{Q_{1}Q_{2}}{4\pi \; ɛ_{r}ɛ_{0}R_{12}^{2}}\mspace{14mu} {Newtons}}} & (1)\end{matrix}$

where Q₁ and Q₂ are the point charges, ε₀ is the permittivity of freespace, ε_(r) is the relative permittivity of free space, and R₁₂ is theseparation between the charges. The ε_(r) for SiO₂ is 3.9 while air is1.0.

The Coulomb forces are linear and the total force due to three pointcharges (Q₁, Q₂ and Q₃) on a reference charge Q_(r) is the sum of theforces due to the three point, charges on the reference charge. Theα_(r1), α_(r2) and α_(r3) are unit vectors and R_(r1), R_(r2) and R₂ aredistances from the reference charge to the other charges in theCartesian coordinate system. The variables in front of the unit vectorsdetermine the magnitude and sign of the forces:

$\begin{matrix}{F = {{\frac{Q_{r}Q_{1}}{4{\pi ɛ}_{r}ɛ_{0}R_{r\; 1}^{2}}a_{R\; 1}} + {\frac{Q_{r}Q_{2}}{4{\pi ɛ}_{r}ɛ_{0}R_{r\; 2}^{2}}a_{R\; 2}} + {\frac{Q_{r}Q_{3}}{4{\pi ɛ}_{r}ɛ_{0}R_{r\; 3}^{2}}a_{R\; 3}\mspace{14mu} {Newtons}}}} & (2)\end{matrix}$

Since each unit vector can be comprised of an x, y and z components,each of these three components can be determined separately from Equ. 2.

The electric field intensity on the z-axis due to a circular sheet ofcharge in the xy-plane as shown in FIG. 2 a is:

$\begin{matrix}\begin{matrix}{E = {\frac{1}{4{\pi ɛ}_{r}ɛ_{0}}{\oint\; {\frac{dq}{r^{2}}a_{r}}}}} \\{= {\frac{1}{4\pi \; ɛ_{r}ɛ_{0}}{\int_{r}{\int_{\theta}{\frac{2{\pi\rho}_{s}r\; {r}\; \cos \; \theta}{h^{2}}a_{z}\mspace{14mu} {Volts}\text{/}{meter}}}}}}\end{matrix} & (3)\end{matrix}$

where ρ_(s) is the surface charge density, r is the radius of the ringwith a width dr, and θ is the angle between the z-axis and the side h.This can be simplified to

$\begin{matrix}{E = {{\frac{\rho_{s}}{2ɛ_{r}ɛ_{0}}{\int_{0}^{\varphi}{\sin \; \theta {\theta}\; a_{z}}}} = {{\frac{\rho_{s}}{2ɛ_{r}ɛ_{0}}\left\lbrack {1 - {\cos \; \varphi}} \right\rbrack}\mspace{14mu} {Volts}\text{/}{meter}}}} & (4)\end{matrix}$

where φ is the displaced angle measured from a point on the z-axis tothe edge of the disk so is a function of z. For instance, a φ of 90°would be an infinite plane while a φ of 45° would be the case where thedistance above the circular sheet of charge equals the radius of thecircular sheet (where d=r in FIG. 2 a). As the point along the z-axisapproaches (0, 0, 0), the displaced angle increases to 90°.

FIG. 2 b illustrates on overlapping view 2-3 of two Coulomb islands 2-4and 2-5. The islands are metallic and have a radius of r and areseparated from each other by the distance of d. Each of these islandscan be formed on separate substrates. If both islands are charged, aforce F will be exerted against the other. Assume that the Cartesiancoordinate system of FIG. 2 a is superimposed against the image of FIG.2 b where the center of the island 2-5 is located at (0, 0, 0) while thecenter of the island 2-4 is located at (0, 0, d). Using Equ. 4, theforce at (0, 0, d) due to the island 2-5 can be calculated bydetermining φ. The force exerted between the two islands can bedetermined if an assumption is made that the entire charge of the island2-4 of charge πr²ρ_(sr) is located at (0, 0, d). Although this is anapproximation, doing so, would result in the approximate force betweentwo circular sheets of charge juxtaposed over one another. As indicatedby Equ. 5, as the two islands are brought closer together, φ increasescausing the cos( ) term to decrease and thereby generating a largerforce between the two islands.

$\begin{matrix}{F = {{\frac{\rho_{s}\rho_{sr}\pi \; r^{2}}{2\; ɛ_{r}ɛ_{0}}\left\lbrack {1 - {\cos \; \varphi}} \right\rbrack}\mspace{14mu} {Newtons}}} & (5)\end{matrix}$

where ρ_(sr) is the surface charge density of the island 2-4 located at(0, 0, d).

Substrates can have rectangular outlines with various aspect ratios andside dimensions that ranges from a fraction of a millimeter to over acentimeter. FIG. 2 c presents a graph 2-6 of the gravitation force ofthree different square silicon substrates 2-9 through 2-11 with theindicated side dimensions where the substrate thickness is theindependent variable. The force as indicated by the grouping 2-12 isread from the vertical axis on the left. The substrate thickness isgiven in micrometers and the thickness of the silicon substrate can bereduced by back grinding. Back grinding can reduce the gravitationalforce by an order of magnitude as indicated by the points 2-7 and 2-8where the thickness was reduced to 65 micrometers from over 500micrometers. Similar curves can be generated using other materials; SiN,GaAs, etc, once their densities are given.

In the graph of 2-6, the right vertical axis provides the voltagenecessary to generate a force corresponding to the points 2-7 and 2-8.The islands are positioned as indicated in FIG. 2 b and the value r wasset to 50 micrometers and the height h was set to 5 micrometers. Thesystem will function at a minimum height that will depend on the degreeof penalization of the two mating surfaces. These islands are alsocalled Coulomb islands and the two juxtaposed islands form a pair ofCoulomb islands. The relative permittivity of the medium between the twoislands is mostly air; so ε_(r) is set to the value one. Please notethis over simplification to simply the analysis; the oxide thicknessbetween the island and the surface of the substrate will be of the orderof 1 micrometer. For the following calculations, the oxides were notincluded. Then Equ. 5 could be solved for ρ_(s) assuming that the twosurface charge densities are equal causing the magnitude of the chargeon each plate to be the same. The surface charge density can bemultiplied by the area of the island where the island is assumed to havea zero thickness; thereby providing the charge Q_(s) associated with thesurface of the island. The capacitance of these islands is approximately0.15 femtofarads. Therefore the voltage applied to the islands is:

$\begin{matrix}{V = \mspace{11mu} {\frac{Qs}{C}\mspace{14mu} {Volts}}} & (6)\end{matrix}$

In order to generate the forces associated with the points 2-7 and 2-8,the potential of each island is indicated as voltage. As the magnitudeof the potential decreases, the charge for a given C also decreases.Equ. 6 was used to determine that the voltage 74 and 220 volts arerequired for one pair of Coulomb islands to generate the force 10⁻⁴ and10⁻³ newtons, respectively.

The force has been estimated using only one pair of Coulomb islands andit has been assumed that the entire electric field is used to generatethis force. Thus, by reducing the thickness of the substrate and therebydecreasing its weight by an order of magnitude, the required potentialcan be decreased almost three times. This has a big impact on severalissues, some are: 1) lower voltages stress the parasitic diode junctionsof the substrate less: 2) lower voltages reduce the stress the gate,drain and source of the devices on the substrate; and 3) generatinglower voltages will drop the power dissipation. Some of the electricfield lines of the Coulomb island in a conventional process without anyspecial considerations will terminate back into the substrate and reducethe Coulomb force between the two substrates. The thickness of thecomponent section of a substrate is less than 10 micrometers (eachmetal/oxide layer consumes about 1.5 to 2 micrometers) so some of theforce will be lost in the substrate unless special modifications aremade, for example, the use of Faraday shields. Oxide substrates alsohelp to deduce the loss. When substrates are levitated over the mothersubstrate, a minimum distance of separation needs to be determined. Thishelps in several ways: 1) a smaller distance of separation requires lessvoltage which in turn dissipates less power; 2) a lower voltage reducesthe stress of materials due to high electric fields; and 3) as thedaughter substrate decreases in area, the ability to maintain thedaughter substrate stable at greater distances of separation becomesmore difficult. If each of the surfaces are planar to within ±1micrometer over a large area, then a separation of slightly more than 4micrometers should be a comfortable distance between these two largearea substrates. However, the amount of required separation between thesubstrates may need to be evaluated for each daughter substrate.

Several of the special conditions include layout and processingtechniques: 1) the introduction of a Faraday shield as discussed laterhelps to prevent some of these electric field lines from terminatingback unto the substrate; 2) any unrelated metallic regions near theislands should be placed further away from the islands; and 3) anyheavily doped substrate elements that can terminate these lines can beetched away to remove their presence if possible. SOI (Silicon OnInsulator) is a good candidate to reduce the lines terminating on thesubstrate for the third point mentioned above.

Although one pair of islands can generate the force necessary toovercome the gravitational force, applying the force to a 1 cm²substrate would require careful placement of the pair of islands andcareful application of the force to lift the substrate. Besides, thehigh values of voltages that were determined earlier would cause avoltage breakdown to occur in the air between the Coulomb islands.Another feature of this invention is the ability to place multiple pairsof Coulomb islands over the surface of the substrate. The spreading ofthe pairs of Coulomb islands over the surface of the substrate hasseveral benefits: 1) the force can be evenly distributed to lift thesubstrate equally and more controllably; 2) the force that each pair ofislands must generate is the total force divided by n, where n is thenumber of pairs of islands; 3) since the force per island decreases, therequired voltage to generate this force also decreases, which reducesthe voltage stress that is applied to materials in the substrate evenfurther; 4) with a large number of pairs of islands, variouscombinations of potential variations applied to and among them allow amyriad of manipulations available to the levitated substrate; and 5) thestability of controlling the levitated substrate becomes easier sincethe forces are spread over a larger area.

The voltage stress involves the various semiconductor diode junctions,oxide and air breakdown concerns. Diodes can breakdown when a maximumreverse voltage is applied across the junction. The source/drain regionsof an MOS device, the emitter/base/drain junctions of a BJT, andparasitic diode formed during manufacturing are examples of diodes.Similarly, thin oxides as formed between the gate and channel of an MOSdevice have a breakdown voltage. As the number of island pairsincreases, the voltage required to generate the net Coulomb forcedecreases; thereby, reducing the voltage stress.

An example is described to explain how the voltage that is applied to amultiple of islands can be decreased as the number n of island pairsincreases. In FIG. 2 c, a potential of 220 volts is required to generatea first force of 10⁻³ newtons for a 1 cm×1 cm substrate with a thicknessof 500 micrometers. A potential of 74 volts is required to generate aforce of 10⁻⁴ newtons for a 0.4 cm×0.4 cm substrate with a thickness of500 micrometers using a similar island pair. In FIG. 2 d, these twopoints correspond to the points 2-18 and 2-17, respectively. If tenpairs of islands are spread over the surface of these substrates, themagnitude of the potential that is required on each island is 69 and 23volts, respectively. At a hundred pairs of islands, the magnitude of thepotential is 22 and 7.3 voltages, respectively. When 1000 pairs ofislands are used the potential applied to each island is only 7 and 2.3volts, respectively, as indicated by the point 2-20 and 2-19. Thus, asthe number of islands is increased, the potential that needs to beapplied to the islands is decreased, thereby decreasing the voltagestress applied to and between the substrates in the system. Thebreakdown voltage of air, Si and SiO₂ are approximately 3E4, 3E5 and 5E6volts/centimeter, respectively. The shaded area indicates where thebreakdown voltage of air would not be exceeded for a gap of 5micrometers. Fortunately, an oxide layer coats each Coulomb island andthis would tend to increase the maximum breakdown voltage between twojuxtaposed Coulomb islands. Secondly, if the thickness of the substrateis decreased, the new set of the three corresponding curves in FIG. 2 dwould be shifted downwards offering the possibility of these substrateshaving lower numbers of Coulomb islands.

FIG. 2 d(1) reproduces FIG. 3 from a publication by R. Fearing entitled“Survey of sticking effects for micro parts handling”, IntelligentRobots and Systems 95, Proc. 1995 IEEE/RSJ Inter, Conf. Aug. 5-9 1995,pp. 212-217. FIG. 2 d(1) depicts the gravitational, electrical, van derWaals and surface tension where the attractive force is between a sphereand a plane. In a dry air environment, a situation where the Coulombforces of our invention can be utilized, surface tension can bedisregarded. Thus, we see that gravity equals the van der Waals force ata radius of about 200 micrometers. Note that the electrostatic forceexceeds the van der Waals at a radius of about 1 millimeter. The finaldesign that is chosen needs to balance the mass of the substrate(gravity) against the number, planar area and voltage of the Coulombislands. For smaller substrates, these variables need to be reexaminedto safely overcome the van der Waals force.

FIG. 2 e depicts a substrate 2-21 with a foundation portion 2-2supporting the component portion 2-4 and the division between them 2-22.A coulomb island 2-23 is located in 2-4. The island 2-23 is chargedpositively 2-25. Negative charges or impurities 2-24 can attach to thesurface of a substrate in an uncontrolled environment. This conditionwould attempt to neutralize the benefit of fabricating a coulomb islandsince the electric field intensity formed outside of the substrate isreduced. A hermetically sealed package and better passivation procedurescan be used to reduce this concern.

FIG. 2 f and FIG. 2 g both depict the cases (2-26 and 2-28) where theexposure to an environment containing impurities is reduced and theelectric field intensity extends away 2-27 and into 2-30 due to thepositive charge 2-25 and the negative charge 2-31 in the coulomb islands2-23 and 2-29, respectively. The coulomb islands should be as close tothe surface of the substrate as possible to maximize the force thatwould be applied to an opposing and juxtaposed substrate that containcharged Coulomb islands.

FIG. 3 a reveals a cross section view of a substrate 3-1 containing aCoulomb island 3-5 in the component portion 2-4 with an access opening3-2 for a probe. The top surface 3-3 may be covered with an oxide layerand a pacification layer 3-4. The Coulomb island 3-5 should be placed asclose as possible to the surface 3-3 and as far as possible from anyunassociated metallic conductors in the region 3-6. It is desirable tohave the electric field intensity lines exit the surface 3-3. This wouldprovide greater control of the levitation process if the electric fieldintensity was prevented from being terminated in the substrate. If notstated explicitly, numbers (e.g., 2-2) which were identified earliercarry the same meaning.

FIG. 3 b shows 3-7 and the formation of a positive 3-10 and negative3-11 charges forming on the top and bottom of the Coulomb island 3-5,respectively. By bringing a negatively charged sheet 3-9 in an externalplate 3-8 close to the Coulomb island 3-5, induced charging causes thecharge distribution on the coulomb island to have a positive sheet 3-10adjacent to the plate 3-8 and a negative sheet 3-11 formed on itsopposing side. Note that the total charge on the Coulomb island 3-5 iscurrently neutral. Furthermore, for the quasi-static case, the electricfield intensity inside the Coulomb island 3-5 is zero and all inducedcharges move to the surface of the Coulomb island 3-5. The chargedistribution is shown to be evenly distributed; however, the shape ofthe metallic sheet can cause some of the changes to group at the cornersand create an uneven distribution. To simplify the discussion, an evendistribution over the surface was assumed. Furthermore, note that thepositively induced charge of 3-10 formed in the Coulomb island 3-5 nowattracts the negatively charged sheet 3-9 in the external plate 3-8.This is known as the induced force.

The next step is to remove the negative charge from the coulomb island3-5. FIG. 3 c illustrates the situation 3-12 when a probe 3-14 which isconnected to ground is connected to the island through the opening 3-2.The negative charge 3-13 a is discharged to ground indicated by the path3-13. FIG. 3 d shows the probe 3-14 being disconnected from the island3-5. The positive charge is located on the top surface of the Coulombisland as illustrated in 3-15 due to the presence of the negativelycharged plate 3-8.

Once the plate 3-8 is removed, as illustrated in FIG. 3 e, the positivecharge 3-9 redistributes itself over the surface of the coulomb island3-5 to insure that the electric field intensity parallel to the surfaceof the coulomb island 3-5 is zero. This redistribution of charge causesthe formation of two electric field intensities 3-17 and 3-18 inopposing directions. FIG. 3 f shows the surface view 3-19 of the coulombisland 3-5. An approximate representation of the charge distribution 3-9a on the surface of the island is depicted in the view 3-19. Although arectangular island is illustrated, the island can have a variety ofshapes; circle, square, triangular, or any geometric shape bounding asurface area. Furthermore, these islands can also contain perforationsor openings within the boundaries of the shape. Charges in metal tend tomove towards the sharp corners and by the proper placement of theseopening (which create corners) the regular distribution of corners canoffer a more uniform charge distribution over the surface of the shape.Since the islands can have variety of shapes, this specification willuse the rectangular island (unless mentioned otherwise) without openingsto simplify the diagrams and provide a simple explanation of theinvention. Note that the dotted line 3-20 in FIG. 3 f represents thecross sectional view illustrated in FIG. 3 e.

The cross sectional view 4-1 in FIG. 4 a illustrates the introduction ofa second plate 4-2 juxtaposed and placed beneath the Coulomb island 3-5.The plate 4-2 can be set to a given negative 4-4, ground, or a positive4-4 a voltage potential using the switch 4-5. Setting the switch to theminus voltage 4-4 creates a negative charge distribution 4-3 on theplate 4-2. The electric field intensity 3-18 starts at the positivecharge 3-9 and terminates on the negative charge 4-3. The net electricfield intensity leaving the surface of the substrate is indicated by theelectric field intensity 3-19. The corresponding top view 4-6 a is givenin FIG. 4 b. Note that by comparing the surface charge distribution 3-9a in FIG. 3 f with the surface charge distribution 3-9 b illustrated inFIG. 4 b, the potential applied to the plate 4-2 can be adjusted todecrease the surface charge distribution 3-9 b (visible by the reducednumber of “+” symbols). The electric field intensity 3-19 leaving thetop surface of the coulomb island 3-5 has been reduced. The plate 4-2creates a Faraday shield for the Coulomb island 3-5. The Faraday shieldis a metallic sheet and coupled metal components (vias, traces, etc.)that act together to shield the Coulomb island from the remainder of thesubstrate. The shield which is fabricated in the substrate is a barrierwhich attempts to give the Coulomb island autonomous behaviorindependent of the remainder of the substrate. Ideally, the Faradayshield should isolate the Coulomb island. For example, the metaltrace/via stack 4-6 which extends the Faraday shield surrounding theisland can be used all around the perimeter of the Coulomb island. Thiswould help provide a better isolation of the Coulomb island. A secondfeature of the Faraday shield is that a potential can be applied to theshield to influence the behavior of the Coulomb island. The adjustmentof the negative potential 4-4 can be used to directly alter the surfacecharge distribution which in turn alters the electric field intensity3-19. This is one of the benefits of the Faraday shield since theelectric field intensity associated with the top surface of the coulombisland can be adjusted which in turn can be used to control the Coulombforce being applied to another juxtaposed and closely spaced Coulombisland. The cross sectional view given in the diagram 4-1 corresponds tothe dotted line 4-7 in FIG. 4 b.

FIG. 4 c illustrates the case 4-8 where the voltage potential 4-4 awhich is positive is applied to the plate 4-2. A sheet of positivecharge 4-9 forms on the plate 4-2. The positive potential on the plate4-2 causes the electric field intensity 3-19 to increase. As before byadjusting the magnitude of the voltage potential 4-4 a, the chargedistribution 3-9 c in FIG. 4 d can be increased. Thus, the Faradayshield can be used to control the electric field intensity 3-19 andthereby control the magnitude of the Coulomb force being applied toanother juxtaposed charged Coulomb island. In addition, the voltagepotentials (4-4 and 4-4 a) can be applied to the switch 4-5 using eitherexternally provided voltages or by generating the voltage potentials onchip using well know voltage generating circuits such as charge pumpswhich are used widely in non-volatile memories.

FIG. 5 a shows a cross sectional view 5-1 of a Coulomb island 5-8 with aFaraday shield 5-7, separated by an oxide layer 5-8 a. An oxide layer5-8 b is beneath Faraday shield 5-7. Two small openings 5-3 and 5-4 inthe oxide allow both plates to be mechanically probed. Since the Faradayshield 5-7 is further below the surface 5-2, a via 5-6 and metal plug5-5 form the contact and provides an ohmic path to the probe point 5-4.One of the advantages of probing the metallic plate is that once theprobe establishes a charge on the plate, the leakage resistive path isvery high once the probe is pulled away allowing the island or shield tomaintain the charge for a long time. This probe can be an external probe(test-like) or an internal one (formed by a MEMS structure). However, ifsemiconductor switches are used to deposit charges onto the metallicplates, the device provide a leakage path and will discharge the platein a shorter amount of time. In this case, the plate would have to beperiodically re-charged at specified intervals. On the other hand, inthe case of the external probes, the Coulomb island and Faraday shieldcan be charged during the testing of the device at wafer level. Once thewafer is sawed into individual substrates (dice) these substrates usinga pick and place tool can be placed on a mother substrate which has itsCoulomb island and Faraday shield similarly charged. The Coulomb forcesdeveloped between the Coulomb islands on the mother and individualsubstrates can be used to hold the substrates together. The next stepwould be to prepare these components for package assembly. Then, oncethe packaged device is complete, the daughter substrates can bereconfigured into a desired system.

FIG. 5 b shows a cross sectional view 5-9 of a probe 5-10 applying anegative voltage 4-4 to the Coulomb island 5-8. The negative voltagecauses charge to form at the surface as the sheets 5-13 and 5-14. Notethat in reality the charge covers all sides of the island to reach anequilibrium condition although only the top and bottom of the islandhave been discussed to simplify the explanation. The lower sheet ofcharge 5-14 causes the shield 5-7 to build an induced charge of apositive sheet 5-11 and a negative sheet 5-12 as shown.

FIG. 5 c shows a cross sectional view 5-15 of a probe 5-10 applying thenegative voltage 4-4 to the Faraday shield 5-7 through the opening 5-4.The potential can be adjusted to form negative sheets of charge 5-16 and5-12 on the surface of the shield 5-7 and a negative sheet of charge5-17 on the surface of the island 5-8. FIG. 5 d illustrates the finalcross section view 5-18 once the probe is removed. The Faraday shield5-7 can be used to shield the Coulomb island 5-8 from the remainingsubstrate beneath the shield.

FIG. 5 e shows a cross sectional view 5-19 of a negative voltage supply4-4 applying the negative voltage 4-4 through the switch 4-5. Thepotential can be adjusted to form negative sheets of charge 5-13 and5-14 on the surface of the island 5-8. An induced positive charge 5-11is formed on the surface of the shield 5-7 and a corresponding negativecharge 5-12 on the opposite side. As in FIG. 4 a, a metal trace/viastack is formed on the right top side of the shield. FIG. 5 fillustrates the final cross section view 5-20 once the shield is has anegative potential 4-4 b applied through the switch 4-5 a. The Faradayshield 5-7 is charged negatively as indicated by the two sheets ofcharge 5-12 and 5-16. The Faraday shield 5-7 shields the Coulomb island5-8 from the remaining substrate beneath the shield.

Since the island and shield in FIG. 5 f are connected to switches andpower supplies, there will be a parasitic leakage path through thecircuitry to slowly reduce the charge that is stored on the shield andisland. This charging is volatile and will always require that thecharge is replenished at periodic intervals. Power dissipation occurswhen the shields and islands are charged; however, the performance ofthis charging circuit can be quite fast since active drivers with lowimpedance can charge and discharge the shields and islands innanoseconds. The non-volatile islands/shields, those fully surrounded bya dielectric layer, can retain the charge for years and can maintain asubstrate levitated dining this time period. A combination of volatileand non-volatile charged islands/shields can be used to move substratesduring a reconfiguration of a system; the determination of which one touse will depend on the requirements given in a specification of thedesign.

FIG. 6 a illustrates a prior art FAMOS (Floating GateAvalanche-injection MOS Memory) device 6-1. The foundation portion 2-2supporting the component portion 2-4 is shown. The foundation portionholds the source 6-3/dram 6-5 and the channel of the device (not shown).The component portion 2-4 has the oxide layers with thicknesses 6-7 and6-4 that isolate the floating gate 6-6 with a height 6-8. A view fromthe top is indicated by the arrow 6-2.

FIG. 6 b depicts the top view 6-2 of the source 6-3 and drain 6-5 alongwith the floating gate 6-6. The floating gate 6-6 in this device iscompletely surrounded by oxide; thus, the gate is isolated from theremainder of the device 6-1. The opening to the source/drain regions areformed by the contact openings 6-9. F-N (Fowler-Nordheim) tunneling isused to charge the floating gate 6-6 and since the floating gate 6-6 isinsulated, the charge can be held indefinitely. This is known as anon-volatile device since the charge can be held even after the power isremoved from the substrate. This is another way of charging theinsulated sheet; however, the sheet or the floating gate 6-6, in thiscase, is close to the substrate and can have a large area. Thus, theelectric field intensity would mostly exist mostly in the gap betweenthe floating gate 6-6 and the channel of the device (within thethickness 6-7).

As shown in FIG. 6 c, the 2-D view with perspective 6-10, shows theFAMOS device connected through a series connection of vias and metalplugs (6-11, 6-13, 6-15 and 6-12, 6-14) to the Coulomb island 6-16 whichis located close to the surface 6-19 of the substrate. The componentregion 2-4 includes all components between the foundation portion 2-2and the surface 6-19. This region is used to form the components such asthe oxides, vias, metal plugs, metal wires, Coulomb island, pacificationlayer, etc. The pacification layer is the oxide 6-17 and 6-18 layers.The distance of the Coulomb island 6-16 from the surface 6-19 is shownas 6-20 while the distance to region 2-2 is 6-21. F-N tunneling of thefloating gate 6-6 can be used to charge the Coulomb island 6-16.Particularly since the floating gate 6-6 is now resistively connected tothe Coulomb island 6-16 through the vias and metal plugs. The area ratioof the floating gate 6-6 to the Coulomb island 6-16 is a variable andcan be controlled to achieve the desired charging rate of the island6-16. Note that the entire structure comprising the poly floating gate6-6, the vias/plug stack and the Coulomb island 6-16 are isolated fromthe remainder of the substrate by an oxide barrier. The arrow 6-22indicates the cross sectional view given in the next Figure.

A cross sectional view 6-22 of the 2-D view with perspective 6-10 isillustrated in FIG. 6 d. All similar numbered items correspond to thesame definition as given earlier. The floating gate 6-6 is shown to stepup due to the field oxide with a height of 6-23. The drain 6-5 of theFAMOS device is shown and is superimposed over the source 6-3 preventingits view. An optional opening 6-24 allows a probe to charge the island6-16 and the elements that are ohmic connected to the islands.

The Faraday shield 6-29 has been added in the cross sectional view 6-25as indicated in FIG. 6 e. The benefits of the Faraday shield 6-29 weredescribed earlier and do not require further explanation. The shield6-29 can be grounded or switched through switch 6-26 to either apositive 6-28 or negative 6-27 potential. The via/plug stack passesthrough the Faraday shield 6-29 without making contact to the shield. Inaddition, the Coulomb plate can be connected to other non-volatiledevices simultaneously as illustrated by the partial view of the devicehaving the dram 6-30. The FAMOS device with the drain 6-5 can be used tocharge the island 6-16 to a negative potential while the additionalnon-volatile device with the drain 6-30 depending on its design can beused to remove the negative charge, inject (positive charges) holes orremove holes. Thus, several non-volatile devices can be connected to theCoulomb island 6-16 simultaneously where each non-volatile device canperform a different functional procedure of charging/discharging theCoulomb island.

FIG. 7 a depicts a prior art SAMOS device 7-1. This is very similar tothe FAMOS device with the exception that an additional gate 7-5 has beenstacked over the floating gate 6-6. These devices are also known as aEEPROM (Electrically Erasable Programmable Read Only Memory). The gate7-5 is called the control gate and is used to enable the erasure andprogramming of the non-volatile device. The control gate is connected toa voltage source and is separated from the lower gate by the distance7-3 and is separated from the foundation by the distance 7-2. Thethickness 7-4 of the control gate 7-5 is shown. The arrow 7-6 indicatesthe view given in FIG. 7 b. The top view 7-6 illustrates the controlgate 7-5 with an overlap area 7-9 that contains two contacts 7-8.

A cross sectional view of the SAMOS device is given in FIG. 7 c alongwith the inventive Coulomb island 6-16 which is charged negatively(either by the non-volatile device with the drain 6-5 or by probing theoptional opening 6-24) and is connected to the floating gate 6-6 by thestacked via/plug structure 6-11 through 6-15. The via/plug structureshows that the substrate uses three levels of metal; the invention isnot limited to this but can be used in any multi-metal layeredsubstrate. Although, the non-volatile device has been shown to be underthe island 6-16, the non-volatile device can also be located in areaswhere there is no island overhead. The numerical identifiers that matchthe identifiers mentioned earlier are similar in nature.

In the cross sectional view 7-11 given in FIG. 7 d, a Faraday shield7-12 has been added below the island 6-16 and can be connected to avariable power supply. The switch can be mechanical (MEMS) or formedfrom active devices.

FIG. 7 e illustrates the cross sectional view 7-14 where the Coulombisland being charged positively by the device with the drain 7-15 whichenergizes holes in the channel and injects them into the floating gate6-6. Finally, the cross sectional view 7-16 shows the introduction of aFaraday shield 7-12 that is charged positively by the potential supply6-28. As before, the device associated with the drains 6-5 and 7-15 canbe different devices that perform different F-N tunneling capabilities(i.e., electron charging, hole charging, discharging electrons,discharging holes).

Wafer bonding can be used to create various substrate structures. FIG. 8a shows a cross sectional view 8-1 showing two substrates 8-2 and 8-4that are part of their respective wafers. The substrate 8-2 can becomprised of a component layer 8-3, while the other substrate can have ablanket coverage 8-5 of electrons 8-6 that were injected using anelectron gun (for example, see U.S. Pat. No. 7,217,582). The twosubstrates can be wafer bonded together to form the final substrate asillustrated in FIG. 8 b. The interface 8-8 joins the two substrates 8-2and 8-4 into the final substrate 8-7.

The cross section view 9-1 in FIG. 9 a illustrates two substrates 9-2and 9-3 forced or held together by the Coulomb force generated by thenegative charged island 9-7 and the positive charged island 9-8 whichare separated from each other by the distance 9-6. The opposite chargeon each island causes an attractive force to develop. Their commonsurface is 9-4 and the electric field intensity 9-5 starts on a positivecharge and terminates on a negative charge. Note that the conventionalCMOS process can be used to form these charged islands: thus, for someof the inventions presented in this specification MEMS processing is notused. This cuts down the mask count to perform the processing of thesubstrate and decreases the cost.

FIG. 9 b illustrates the cross sectional view 9-9 where the charge ofthe top island 9-8 has been changed to a negative charge. Now the twoislands repel one another as depicted by the increased displacement ofthe distance 9-10. In addition, the electric field intensity 9-12 linesterminate on the negative charge in both islands and arrive from outsideboth substrates 9-2 and 9-3. An assumption is made here that theremaining portions of the substrate do not contain charges. This is anover simplification, since the substrates as shown would contain somepositive charges such that some of the lines of the electric fieldintensity would start from them and terminate on some of the negativecharges within either island. The displacement 9-11 between thesubstrates in that case would be less than what is illustrated. A way ofrecovering some of the displacement 9-11 would be to introduce Faradayshields into each substrate.

FIG. 10 a illustrates the cross section image 10-1 of two substrates(10-17 and 10-18). The top substrate 10-17 has multiple Coulomb islands10-2 through 10-8 while the lower substrate 10-18 has the Coulombislands 10-9 through 10-15. This is the first presentation of multipleislands on one substrate. These islands help to explain how thesubstrates can be repelled from one another yet remain in levitationstate. For example, the islands 10-2, 10-3 10-7 and 10-8 from the topsubstrate 10-17 are repelled from the underlying islands 10-9, 10-10,10-14 and 10-15 within the lower substrate 10-18, respectively, sincethey have a like charge. However, the inner islands 10-4 through 10-6 ofsubstrate 10-17 attract the islands 10-11 through 10-13 of substrate10-18 since their charges are opposite. The charges on the islands 10-4through 10-6 have an increased positive charge as indicated by thedouble “plus” signs. These charge distributions on the islands causesthe two substrates to be separated by the distance 10-16.

In FIG. 10 b, 10-19 illustrates the situation where the increased chargeon the islands 10-4 through 10-6 has been reduced from the initialvalue. The charge can be altered by using one of the earlier techniquesgiven; such as, F-N tunneling or Faraday shield potential variation, forexample. Thus, the attractive force decreases and causes the distance10-20 between the two substrates to increase which adjusts the height ofthe daughter substrate.

What has not been shown is how the substrates remain in a stableposition once they are separated and levitated. There are sensors on thesubstrates that can measure their distance at several points of thesurface of the substrate and provide feedback information to a controlunit that can use this information to adjust the amount of charge in theislands. Doing so allows the substrate to remain levitated and inequilibrium. This daughter substrate control unit can be located eitherin the daughter substrate, in the mother substrate, or distributedbetween both. This forms a feedback system which dynamically correctsfor and adjusts the position of the two substrates to each other. Thesensors can be capacitive in nature and can be used to measure distance,acceleration, velocity, position or identity of each substrate. Anadditional control unit that orchestrates the movement of all daughtersubstrates with respect to one another can also be used. The additionalcontrol unit can also be in communication with the daughter controlunit. In addition, the sensors can also be mechanical in nature as well.A MEMS structure can be used for an accelerometer and can be mounted ona daughter substrate to monitor its acceleration.

The cross section 11-1 illustrated in FIG. 11 a illustrates using onlyrepulsive force to maintain a substrate levitated. The system consistsof an upper mother substrate 11-2 and a lower mother substrate 11-5 thatare firmly held in position. These two substrates can be held in placewith respect to each oilier by being supported inside of a package aswill be shown later. The inner daughter substrate consists of two backto back substrates 11-3 and 11-4 that were wafer bonded together alongthe dotted line 11-21. The Coulomb islands 11-6 through 11-12 insubstrate 11-2 having the negative charges repel the Coulomb islands11-13 through 11-19 in substrate 11-3. In addition, the Coulomb islandsin the substrates 11-4 and 11-5 are negative. Thus, the inner daughtersubstrate is repelled from the bottom as well. Note in particular thatthe Coulomb islands 11-23 through 11-25 have a negative charge. Thecharge of all the Coulomb islands depicted is negative; thus, all forcesare repulsive. Since the repulsive charges occur on opposing sides ofthe combined daughter substrate (11-3 and 11-4), the combined daughtersubstrate can be held in a levitated position as indicated by the twodistances 11-20 and 11-22.

The cross section 11-26 illustrated in FIG. 11 b depicts the situationwhen the Coulomb islands 11-23 through 11-25 are changed to a positivecharge. Note that the distance 11-20 increased, while the distance 11-22decreased due to the attractive force between the positive and negativeislands. It would also be possible to decrease the distance 11-22 tozero and allow the combined daughter substrates to make contact with thelower mother substrate 11-5. Note that the region 11-27 contains bothfoundation portions 2-2 b and 2-2 c of daughter substrates 11-3 and11-4, respectively. The backs can be ground before being wafer bonded toreduce the mass of the combined daughter substrates. A lower massrequires less force to position the daughter substrates and will reducethe charge that is placed on the islands requiring a simpler chargingsystem. The Coulomb islands of the daughter substrates are located inthe component portions 2-4 b and 2-4 c.

FIG. 11 c shows a cross sectional view 11-28 where a third variation ofusing different substrates are depicted. The upper mother substrate11-31 and the upper daughter substrate 11-33 now has a blanket electronimplantation generating negatively charged islands 11-30 and 11-32 nearthe surface of each substrate. The electrons are injected into an oxidelayer with a low energy implant such that the charge is close to thesurface. The upper daughter substrate can be an oxide and is waferbonded to the lower daughter substrate 11-4 at the interface 11-29. Itis also possible to grow an oxide onto the back side of the 11-4substrate. In this case, the electrons can be implanted directly intothis oxide layer eliminating the need for bonding the upper substrate11-33 to the lower substrate 11-4. The inner daughter substrate canagain be levitated.

FIG. 12 illustrates several possible ways to electrically connectsubstrates together. In FIG. 12 a, the cross sectional view 12-1 showsan upper substrate 12-2 and a lower substrate 12-6, where the Coulombislands 12-3, 12-5, 12-7 and 12-9 are each charged positive; thus, thesubstrates repel. Each substrate has a metallic region 12-4 and 12-8 intheir component section. These regions can be formed using surfaceinterconnect and via metal segments. In FIG. 12 b, as 12-10 depicts, thecharge on the Coulomb islands 12-7 and 12-9 have been made negative.Now, the substrates attract and connect to one another along theinterface 2-11. The dotted circle 12-12 is the view illustrated in FIG.12 c. Note that the metallic regions have a post within the dottedellipse 12-13 so that electrical conductive (or heat conduction) pathcan be formed between the upper and lower metallic segments. The finalmagnified view 12-13 given in FIG. 12 d further highlights the posts12-15 and 12-14. These posts are metallic and can be formed either byetching back the oxide to expose the highest layer metal, or additionalprocessing steps can be performed to deposit the posts over the metallicregions 12-4 and 12-8. A processing step of wet or dry etching can beused to remove the oxide to expose the metallic traces. If thefoundation portion has a non-oxide material, an additional etching stepmay be required. On the other hand, a deposition technique such assputtering can be used to add material to the exposed metal surface tocreate a post.

The Coulomb forces, holding the two substrates together at the posts,can be varied according to a program stored in a control unit that canbe located in one or more of the substrates. A sequence can cause theCoulomb force to force a lateral movement (shearing force) of one of thesubstrates. This will cause the surface of the connected metal posts tonib each other so that any oxide layer formed on the connected surfacesof the posts undergoes abrasion and/or scraping which exposes theunderlying metal. An improved metallic connection can then be formedbetween the two adjoining posts once the underlying metal is exposed.The shearing force can also be used to disconnect the substrates fromeach other. In addition, a MEMS ultrasonic transducer can be enabled tointroduce vibrations to aid the shearing force being applied to theposts.

FIG. 12 e illustrates another cross section view 2-16 which containsMEMS devices 12-20 and 12-19 in the upper substrate 12-18 and the lowersubstrate 12-17, respectively. Two of the Coulomb islands 12-21 and12-22 are shown to be positive. In FIG. 12 f the view 12-23 illustratesthe two MEMS devices close to one another within the dotted circle12-24, since opposing Coulomb islands have opposite charges. The closeup view 12-24 in FIG. 12 g further illustrates the MEMS devicecomprising a movable metal shaft 12-28 connected to a positively chargedplate 12-26. The shaft can be moved by applying a charge to thejuxtaposed Coulomb island 12-25. The lower substrate contains themovable metal shaft 12-29 connected to a positively charged plate 12-27.The shaft can be moved by applying a charge to the juxtaposed Coulombisland 12-26. FIG. 12 h applies a positive charge to the islands 12-25and 12-24 thereby forcing the two movable shafts to approach and connecteach other. The cantilevered arms 12-32 and 12-31 connect to the metalshafts and can provide electrical connectivity to the rest of theirsubstrate. Note that the lower MEMS metal shaft can be replaced by themetallic regions mentioned in FIG. 12 a having a post allowing theformation of a hybrid connection. The top electrical contact is formedusing a MEMS device while the lower contact has an extended post. Thetravel distance for the MEMS device may need to be increased to achievean electrical contact.

A solder bump connection is also depicted in FIG. 12 i. In the view12-33 two substrates 12-34 and 12-35 are back to back. A metallicthrough vias through the substrate are illustrated in both substrates12-38 and 12-39. This forms a metallic conductor between the front andback sides of a substrate. A via can be used to carry electrical power,signals or heat. The Coulomb islands 12-36, 12-37, 12-40 and 12-41 areindicated. However, the force generated by these islands on each otherhas been reduced since they are on opposing sides of the substratesthereby increasing the distance between them. When solder bumps andthrough vias are used in substrates, the connection will become morepermanent since the solder bump is melted and solidified. FIG. 12 jshows the dotted circle 12-44 which identifies the bump 12-43 in theview 12-42. The view 12-45 and 12-46 in FIG. 12 k and FIG. 12 l indicatethe solder bump details. A solder darn formed by 12-47 a-12-47 dconfines the melted solder to remain near the two through vias 12-38 and12-39 and electrically connect the vias together.

Of course, vias that penetrate the entire substrate can be used in thefirst two examples. In addition, for the solder bump case, thesubstrates could also be arranged top to back as well.

A cross sectional view 13-1 of a packaged levitating device isillustrated in FIG. 13 a. The top 13-2 of the package can hold asubstrate having an electron charge 13-3 embedded near the surface. Thebase 13-7 of the package mounts the substrate 13-6 while two substrates13-5 and 13-8 are shown levitating between the two mother substrates13-2 and 13-6. The top substrate of the daughter substrates areillustrated with an electron implanted island 13-4. All island chargesare negative and adjusted in magnitude; thus, the daughter substratesare in a levitated position. Connecting the package to the substrate13-6 can be done using solder bumps, through substrate vias, or bondingwires. Finally, solder balls 13-7 a form the electrical, heat andmechanical connection between the substrates and the PWB board.

In the view 13-9 given in FIG. 13 b, the set of coulomb islands 13-11,13-12 and 13-13 help to levitate the daughter substrates as mentionedearlier. However, RF energy 13-10 is applied to the daughter substratesso that they can receive external power when in the levitation state.For low power applications, the heat dissipation generated within thedaughter substrates may not be an issue and the heat may be radiated tothe inside walls of the package; however, as the power dissipationwithin the daughter substrates increases other means may be required toeliminate heat from the substrates.

FIG. 14 a illustrates a package 14-1 that contains an adjustablecapacitor formed between two substrates. The top of the package 14-2does not contain any islands. The daughter substrate 14-6 is levitatedusing both like (14-7 and 14-12) and opposing (14-8 and 14-13) chargedislands. Similar conditions hold for the remaining islands. The firstrepels while the second attracts; if the force can be balanced then thesubstrate 14-6 can be held in a levitated state. The distance ofseparation 14-3 is indicated. In addition, a bonding wire is shown toconnect an I/O pad to the package pad.

The capacitor consists of parallel metallic plates 14-9, 14-14 and14-15. The metallic plate 14-9 located in the daughter substrate has alarger area and overlaps the areas of the metal plates 14-14 and 14-15which are located in the mother substrate 14-4. A signal can be appliedto the plate 14-14 then capacitively coupled to the plate 14-9. Thissignal then returns capacitively to the lower plate 14-15. Thus, thispath consists of two capacitors in series and the value of thesecapacitors depends on the distance of separation 14-3. Such a capacitorcan be used to measure the distance using electrical circuit techniques.For example, a capacitive bridge circuit can be formed using the seriescapacitors as one of the bridge elements. By measuring the output of thecomparator connected to the bridge circuit, the relative change indistance can be measured. Furthermore, the plate 14-9 can be tappedelectrically and either extract the signal at this point on thesubstance 14-6 or inject a signal into the plate. This capacitor existswhen the daughter is in contact with or being levitated above thesubstrate. As the daughter substrate moves away from the mothersubstrate the capacitance would decrease in magnitude.

Another possible use for these capacitors is to create an adjustable LCtank circuit 14-16. Such a circuit is illustrated in FIG. 14 b. Thenumerical identifiers are the same as in FIG. 14 a except that theircircuit equivalents are given. One lead of the inductor 14-17 isconnected to the lower plate 14-14, while the second lead of theinductor is connected to the lower plate 14-15. The metallic plate 14-9completes the LC circuit. Furthermore, the capacitors are adjustable byaltering the distance of separation 14-3 using the Coulomb force. Notethat the dotted lines show the surfaces of the two juxtaposedsubstrates. As the distance is modified, the frequency of operation ofthe tank circuit is altered. The regenerative circuit is not illustratedto simplify the diagram. (See for example U.S. app 20070018739).

Another use is to measure the frequency of operation of the tank circuit14-16, use a lookup table, match the measured frequency to an entry inthe table, and extract the value of the distance of separation. Such acircuit can be used to measure this distance and be used to applycorrective adjustments to the Coulomb islands so that the separation iscontrolled. This is another way of measuring the separation so that thedaughter substrate can be maintained in a controlled state oflevitation.

In the package 14-18 of FIG. 14 c, similar numbered items as previouslydiscussed are the same. Two new plates 14-20 and 14-21 are illustratedin the substrate 14-19. Each of these plates overlaps the plates 14-14and 14-15 on the lower substrate 14-4, respectively. Each pair of plates14-20 with 14-14 and 14-21 with 14-15 creates two capacitors. Thesecapacitors can be used individually or as a balance pair. For example.FIG. 14 d illustrates a balanced interface circuit 14-22. The block14-24 can be a balanced I/O driver which applies two signals out ofphase with each other to the lower plates 14-14 and 14-15. These signalsare then capacitively coupled to the upper plates 14-20 and 14-19 andthen applied to a balanced receiver 14-23 (For example, see U.S. Pat.No. 5,708,389). As the distance of separation 14-3 changes, the transferof data from the lower substrate 14-4 to the upper substrate 14-19 isbeing captured using digital signals. Because of the larger noise marginof digital signals compared to analog signals, varying the amplitude ofthe received digital signal within a specified range may not effect theinterpretation of the signal. Thus, the digital signals can be capturedand used to provide control, movement, adjustment and identificationcommands to the upper substrate while the daughter substrate is in thelevitation position. Similar circuits can be used to transfer data fromthe upper to lower substrates.

FIG. 15 a illustrates a cross sectional view 15-1 of a package where thedaughter substrate 15-2 contains an inductor 15-4. If the foundationportion is composed of any low resistivity material (e.g., p+±epi,highly doped materials, metallic structures, etc.), the substrate can bepreferably etched to remove this section as indicated by the cut 15-5.In SOI (Silicon On Insulator), the loss is less severe since thefoundation portion is an oxide. The removal of this material decreasesthe losses of the inductor and improves the “Q” of the inductor. Thedaughter substrate is separated by the distance 14-3. The volume aroundthe inductor 15-4 is air which would reduce the eddy current loss in thesubstrate that is typically associated with this volume (for example seeU.S. Pat. No. 7,250,826 and U.S. Appl. 2007018739). The self-eddycurrent loss occurring within the inductor itself can be decreased inone example as indicated in U.S. Appl. 20070176704. As before, a bondingwire 14-11 (only one is shown) is used to connect the I/O pads of themother substrate 15-3 to the a bonding pad of the package. A top view15-4 a of one type of inductor layout is illustrates in FIG. 15 b. Theleads of the inductor are 15-6 and 15-7 and the inductor is typicallyfabricated from a metallic sheet. Finally, the electrical symbol 15-4 bfor the inductor without parasitica is depicted in FIG. 15 c. Althoughthe cut is used to remove conductive material from regions around theregion perpendicular to the coil's plane, the cut can also be usedpreferentially to remove conductive material from regions perpendicularto the Coulomb island's surface to improve the operation of the Coulombisland.

In FIG. 16 a the cross sectional view 16-1 shows a daughter substrate15-2 being held to the mother substrate 15-3 by Coulomb forces. However,just before these two substrates made contact due to the Coulomb force,the substrates, while existing in a wafer form were tested at the waferlevel. During this test, Coulomb islands were probed and charged to agiven magnitude and polarity. The wafers containing the daughtersubstrates were sawn apart and cleaned in a non-conducting environmentso that the probe points do not offer a discharge path. Then, thedaughter substrates can be positioned on the wafer using a pick andplace tool. Once the daughter substrate comes close to the mothersubstrate, the pick and place tool can release the daughter substrate.The electrostatic forces will help snap the daughter substrates intoposition while making physical and electrical contact with the mothersubstrate in wafer form. Different daughter substrates can havedifferent patterns of Coulomb islands enabled. This offers a “key” toonly allow those daughters with a matching charge pattern to “fit” themother substrate at these points. Otherwise, the daughter substrate isnot connected. The physical contact is mechanical in nature in that theportions of the surfaces are in contact to one another and heat flow canoccur between the substrates. The electrical contact is allowingelectrical signals (power, signals or both) to flow between the twojuxtaposed substrates. The mating surfaces of the substrates are planarsince CMP (Chemical-Mechanical Penalization) is used to maintain a flatsurface. Once all of the daughter substrates are placed on the wafercontaining the mother substrate, the wafer can then be cut. Note thatthe daughter substrates are physically in contact with the mothersubstrate; therefore, contaminants will have a difficult time enteringthe mating interface formed between the surfaces of the daughter andmother substrates. Once the mated substrates are packaged, they can thenbe wire bonded to transfer signals and power. Another option is toassemble the daughter substrates after cutting the mother substrate fromthe wafer. Another of connecting the substrates to each other and to thepackage includes the use of solder bumping.

One example of wire bonding is illustrated in FIG. 16 a. A bonding wire16-2 makes contact between an I/O pad of a daughter substrate 15-2 andthe mother substrate 15-3 at the I/O pad 14-10. A second bonding wire14-11 is formed between the I/O pad 14-10 and the package pad. Such astructure would be used to provide power to the daughter substrate.Other possibilities include wire bonding the daughter substrate directlyto the package pad. The inductor 15-4 is close to the surface of themother substrate 15-3. FIG. 16 b illustrates the use of repellingCoulomb forces to lift the daughter substrate 15-2 while still beingtethered by the bonding wire 16-2 to the I/O pad 14-10. The inductor15-4 is now surrounded by air increasing its Q. In addition, power,signal or both leads can be attached to the levitated substrate. Thebonding wires tethered the levitating substrates which can holdoscillators, lasers and other circuits. These wires can help conductheat as well

The way the daughter substrate is moved across the surface is providedin the following figures. A 2-D representation will be used to describethe basic concepts of lifting, moving, and chopping while a 2-D withperspective will be used to give a better understanding by visualizinghow the substrates slide over the mother substrate. The Coulomb islandsare shown to be in a regular or arrayed pattern; however, this is not arequirement. For instance, instead of covering the entire substrate withan array of islands, strips of islands can be formed that bear arelationship to the size of the daughter substrates (either directly orin multiples). Doing so would free up the remaining area for signal,clock and power bussing.

One example of strips of islands is given in FIG. 17 a with the crosssectional view 17-1. Shown is a mother substrate 17-3 with a daughtersubstrate 17-2 that are Coulomb attached to each other by the charges onthe islands 17-4, 17-5, 17-7 and 17-10. The remaining islands 17-6,17-8, 17-9, 17-11 and 17-12 are all located in the substrate 17-3. Notethat the upper substrate 17-2 does not have matching islands at thelocations opposite the islands 17-8 and 17-9. The elimination of theseislands allows for an easier explanation but is not an indication thattheir absence is the only way to build these systems. The locations ofthe islands are left flexible to allow for a variety of possible islandplacements for a given application since these needs for a differentapplication may require a different island placement. In addition, theshape of the Coulomb islands was introduced as being circular: however,the islands can be oval, rectangular, or any geometrical shape. Inaddition, an island will be introduced that has its surfaceperpendicular to the top surface of the mother substrate. Note themarker 17-13 which indicates the initial location of the right edge ofthe substrate 17-2. Finally, the drawings are not necessarily drawn toscale as pointed out earlier.

FIG. 17 b illustrates the view 17-14 where the islands 17-8 and 17-9have been given a charge. The right edge of the daughter substrate ismarked by the line 17-13 and the substrates are still in contact. Thesubstrate 17-2 has a gravitational force 17-15 and the unit vectorforces 17-16 through 17-21 are indicated. The magnitude of these forcesare not shown but can be determined by knowing the size of the islands,their distances, and their charges. Equ. 2 can be used to estimate theunit vector forces and components. The forces 17-16 and 17-18 aredownward since each pair of Coulomb islands: 17-4 and 17-7, 17-5 and17-10 have an attractive force and hold the two substrates together. Theforces 17-17 and 17-19 are repulsive and are due to the two pairs ofsame charged islands: 17-6 and 17-4, 17-9 and 17-5. In addition, theforces 17-20 and 17-21 are attractive and are due to the two pairs ofoppositely charged islands: 17-4 and 17-8, 17-5 and 17-11. Note that thesummation of the unit force vectors indicate that there will be a netforce in the positive x-direction. FIG. 17 c illustrated the crosssectional view 17-25 where the islands 17-7 and 17-10 flip their chargefrom a negative to a positive value. The vector 17-16 and 17-18 havechanged direction by 180°. The positive y-component forces of theCoulomb forces should add up to be greater than the gravitational force17-15 in magnitude. An extra force may be needed to overcome the suctionforces between the two substrates. Stiction is a force where thesurfaces that are in contact develop an attractive force due to Van derWall forces for example and an additional force in the y-direction maybe needed to overpower this force. In addition, an x-direction force canapply shear force between the two substrates. Once the daughtersubstrate disconnects, it moves upwards as shown by the displacement17-24. The daughter substrate also slides in the positive x direction asshown in FIG. 17 d since this is in the direction of minimum energy. Asthe daughter substrate moves in the positive x-direction, the distancebetween the similarly charged pairs of islands (17-4 and 17-9; 17-5 and17-12) decreases such that the repelling force increases in magnitude.This acts as a stop for the daughter substrate. The net movement of thedaughter substrate in the positive x-direction is indicated by thedotted line 17-27.

FIG. 17 e shows the charge on the islands 17-7, 17-9, 17-10 and 17-12being neutralized. The only forces are the attractive forces 17-20 and17-21 and the repelling force 17-17. These forces continue moving thesubstrate in the x-direction and prepare the positioning of the daughtersubstrate over the mother substrate. Finally, the cross section view17-29 in FIG. 17 f depicts the daughter substrate in the new positionand being displaced by the distance 17-30. The system is ready to repeatthe same movement or introduce a movement into or out of the page. Thereare many ways to perform the charging operation of the islands tocontrol the movement of the daughter substrates. It is easy to see thatthe charge on island 17-7 could have been positive in FIG. 17 e andstill provide the same net result. Another aspect is that thedescription of movement indicates a lift, move, and drop sequence. Thisis not always required. For instance, suppose the daughter was to slideover several islands, then the movement should be lift and move over allislands, then drop to place the daughter substrate into position.

The tuning diagrams 17-31 to make the daughter substrate move in thepositive x-direction are given in FIG. 17 g. The magnitudes of thecharge distribution in each island are not drawn to scale. Note that themagnitudes can also vary linearly 17-32 as a function of time. The setof waveforms shown are one possible combination to move the substrate inthe positive x-direction but others are possible. The y-axis providesthe potentials of several Coulomb islands and how these potentials varyover the x-axis that is segmented according to the figures. Note thatthe positive charge of the coulomb islands 17-4 and 17-5 located in thedaughter substrate remained constant. In this case, the powerdissipation of the daughter substrate can be reduced to a very lowvalue. The next step is to move a substrate vertically against gravity;this issue is covered in the next set of figures.

FIG. 18 a illustrates the cross sectional view 18-1 of the case when thedaughter substrate 18-3 is moving in the positive y-direction againstgravity 18-2. One can appreciate that wafer thinning (such as backgrinding) is very beneficial to ease the movement of the daughtersubstrates since their mass can be reduced. This reduction in mass alsocan reduce the magnitude of the required voltages necessary to activatethe forces associated with the coulomb islands. Thus, the powerdissipation of the system can be reduced if the daughter substrates arethinned to reduce their mass,

In the example given, the mother substrate 18-4 generates the forcesnecessary to move the daughter substrate 18-3 against the force ofgravity 18-2. Although there are only two Coulomb islands, 18-5 and18-6, on the daughter substrate 18-3, the additional placement ofislands would offer a benefit in that the movement becomes performed insmaller movements and thereby providing better control. However, onlytwo islands will be used in this description. The mother substrate 18-4has the Coulomb islands 18-7 through 18-15. The islands 18-7 and 18-10are positively charged. The island 18-7 generates a repulsive force18-17, while the island 18-10 generates the repulsive forces 18-16 and18-22. The arrows indicate the unit vector components of the force. Themagnitudes of these forces are not shown. The islands 18-9 and 18-12through 18-14 are negatively charged. They generate the attractiveforces 18-18, and 18-19 through 18-21, respectively. The summation ofall the positive y-component forces must exceed the force of gravity18-2. Also there should be a negative x-component of force thatovercomes the stiction force and displaces the substrate by the distance18-23. Once the substrate moves upwards a vertical distance 18-30, FIG.18 b shows the cross sectional view 18-25 and the charged islands 18-8and 18-11 that changed their charge from neutral to a positive charge,the islands 18-9 and 18-12 were negative and were changed to a neutralcharge, the island 18-10 which altered the polarity of charge frompositive to negative, and the island 18-15 which went from neutral to anegative charge. The diagram indicates that the direction of the force18-16 flipped in direction to help the substrate move vertically. Force18-17 is still there but has a smaller magnitude since the distancebetween the two charges increased. Forces 18-20 and 18-21 increase inmagnitude to help move the substrate vertically since the distancebetween these respective islands decrease. The components of the forces18-26, 18-27 and 18-29 help to move the substrate in the negativex-direction, while other components of the forces 18-27 through 18-29help to compensate for the force of gravity 18-2. The net movement ofthe substrate shows a vertical displacement 18-30 equal to the “distancebetween the islands” on the mother substrate. Observing the pattern ofthe charged islands on the mother substrate and their relative placementto the daughter substrate in FIG. 18 b illustrates that the pattern issimilar to that shown in FIG. 18 a except the daughter substrate hasbeen shifted one “island distance” upwards. Thus, to continue themovement upwards, the same procedure is repeated over and over again.The control unit identifies the daughter substrate, the direction ofmovement, the

A simplified version of a daughter substrate 19-1 is illustrated in FIG.19 a. The sides of the daughter substrate are 19-2 a through 19-2 d. Atthe corners of the substrate are coulomb islands 19-3 through 19-6. A2-D view with depth perspective 19-7 is depicted in FIG. 19 b. Thedaughter substrates is placed over the mother substrate 19-8 and thesides of the daughter substrate (19-2 a through 19-2 d) are madetransparent so that only the coulomb islands 19-3, 19-4, 19-5 and 19-6are visible. The mother substrate has an array of islands located atCartesian coordinates. The lower left shows the (0, 0) coordinate, whilethe (5, 5) location corresponds to the island in the upper right corner.The daughter substrate is placed over the array of the mother substratesuch that the island 19-3 is over the island at (1, 4), 19-4 is over theisland at (4, 4), 19-5 is over the island at (1, 1) and 19-6 is over theisland at (4, 1).

A minimum energy surface is made by applying potentials in certainsequences to the Coulomb islands. Suppose the daughter substrate is tomove in the positive y-direction, then the energy surface surroundingeach of the islands on the daughter substrate need to have a minimumenergy barrier in the positive y-direction and a larger energy barrierin the three directions of negative y-direction, positive x-directionand negative x-direction. Assume that the islands of the daughtersubstrate are charged positively. In addition, the islands directlyunder these islands on the mother substrate (1, 4), (4, 4), (1, 1) and(4, 1) are also charged positively. Thus the daughter is repelled fromthe surface of the mother substrate. A unit force vector would pointfrom the island of the mother substrate to the juxtaposed island of thedaughter substrate (but is not shown). The remaining unit force vectorson the island 19-3 due to the adjacent islands are indicated. Whateveris done in the vicinity of one of the islands of the daughter substrateon the mother substrate is repeated at the other three islands as well;thus, the formation of the minimum energy surface can be made for one ofthe daughter islands which can then be repeated at the three otherislands. The island at (1, 1) is used as the example. The next step isto place a positive charge at the islands forming a semi-circle shapesurrounding the island located at (1, 1). These include the islandslocated at the coordinates (0, 1), (0, 0), (1, 0), (2, 0) and (2, 1).The forces that the island 19-5 would experience are indicated by thedirection of the corresponding unit vector forces. In other words, as anexample, the force 19-9 on the island 19-5 is shown to exist from theisland at (0, 0) of the mother substrate to the island at 19-5 of thedaughter substrate. Thus, the semi-circle formed earlier acts as abarrier to prevent tire island 19-5 from moving in the negativey-direction and either of the positive or negative x-directions. Thus,this energy barrier is not at a minimum in these directions. However, inthe positive y-direction the barrier is less if the charge of theislands at (0, 2), (1, 2) and (2, 2) are set to a neutral charge. Toenhance the reduction of the barrier further, the islands at (0, 2), (1,2) and (2, 2) can be set to have a negative charge. Now, a force existsto move the island 19-5 in the positive y-direction. Thus, a minimumenergy barrier in the positive y-direction was created around the island19-5 of the daughter substrate 19-1. These forces allow the island 19-5to be levitated and slide in the positive y-direction. By symmetry, eachof the remaining islands of the daughter substrate have a similar energybarrier allowing the entire daughter substrate 19-1 to be easily movedin the positive y-direction. The net force required would be evenlydivided between the four islands of the daughter substrate. Each islandonly has to generate ¼ of the overall force. This can reduce the voltagenecessary to charge the islands and can reduce the power dissipation ofthe system.

To help explain the next figure, some symbols need to be introduced.FIG. 20 a a single island symbol where the island can be neutral,positive or negative. FIG. 20 b illustrates the final symbol when twoislands are superimposed on each other. For example, the top row shows anegative island being placed over a negative island, the arrow points tothe final symbol. The next row places a positive island over a positiveisland generating the final symbol on the right. The third row shows aneutral island placed over a positive island which generates a positivesymbol. The fifth row shows a positive island being placed over anegative island; the symbol generated is a crossed box. FIG. 20 cillustrates those symbols which generate forces between the two islandsforming the symbol. The symbols in the first two rows experience arepulsion force between the two juxtaposed islands while the symbol inthe third row experiences an attractive force between the two juxtaposedislands.

FIG. 20 d illustrates the placement of the coulomb islands in the mothersubstrate 20-1. The islands at (2, 1), (5, 1), (5, 4) and (2, 4) arecharged positively as indicated by the symbol. A daughter substrate 20-2is shown in FIG. 20 f with sides 20-3 and Coulomb islands 20-4 at thecorners of the substrate. The daughter substrate has negatively chargedislands.

The process of moving the daughter substrate in the y-direction whichwas shown earlier is repeated in FIG. 21 to illustrate how these symbolscan be used to modify the energy barrier to impose a linear movement onthe daughter substrate. The system 22-1 in FIG. 21 a illustrates theplacement of the daughter substrate 20-3 over the mother substrate 20-1introduced in the last paragraph. Note the symbol indicates anattractive force being formed between the islands. In FIG. 21 b the topview 21-2 of the adjacent islands are being prepared to modify theenergy barrier. The islands at (1, 2), (2, 2) and (3, 2) are madepositive. The islands at (1, 1), (3, 1) and (2, 0) are charged negative.Note that semi-circle is charged differently when compared to FIG. 19 b.For example, the islands at (1, 0) and (3, 0) are not charged at all.However, there is enough of a repulsion barrier formed by the threecharged islands to push the daughter substrate in the y-direction. Thisalso shows that other charge configurations are possible.

The next step is illustrated in the top view 21-3 shown in FIG. 21 c.The islands at (2, 1), (5, 1), (5, 4) and (2, 4) are charged negativelyas indicated by the symbol and repels the daughter substrate. Theattractive force of the positively charged islands on the mothersubstrate which are located in the next row above each of the islands onthe daughter substrate reduces the energy barrier and forces thedaughter substrate to move in the y-direction. The daughter drops intoplace at the next set of islands located at (2, 2), (5, 2), (5, 5) and(2, 5) as indicated in the top view 21-9 of FIG. 21 d.

A daughter substrate may need to be rotated in place. FIGS. 22illustrate how the energy barrier can be altered to impose a rotationalmovement on the daughter substrate 22-3. In FIG. 22 a the top view 22-1shows that the daughter substrate has internal Coulomb islands 22-2 aand 22-2 b that are charged positively. The corner islands, for instance22-4 c and 22-4 b, are charged negatively. The top view 22-6 depicts themother substrate 20-1 in FIG. 22 b with the daughter substrate 22-1juxtaposed. The Coulomb islands on the mother substrate are at (2, 2),(5, 2), (5, 5) and (2, 5) and are charged positively. The forces atthese juxtaposed charged islands are attractive; thus, the daughtersubstrate is connected to the mother substrate. Finally, anidentification pin 22-5 is placed on the daughter substrate to helpidentify the amount of rotation.

FIG. 22 c illustrates the top view 22-7 of the charging of the adjacentislands to create the energy barriers appropriate to perform a rotation.By symmetry, as before, only the forces with one corner are explainedsince the remaining corners are similar in structure, would be chargedthe same and would therefore behave similarly. The corner associatedwith the Coulomb island 22-4 b that is charged negatively is used toexplain the rotation. As mentioned earlier, the island at (5, 5) on themother substrate is charged positively. The islands at (5, 4) and (6, 5)are charged negatively. The islands at (4, 5), (4, 6) and (5, 6) arecharged positively. In addition, the island at (3, 4) is chargednegatively to help attract the inner island 22-2 b on the daughtersubstrate. The top view 22-8 in FIG. 22 d shows that the island at (5,5) of the mother substrate flipped the charge from positive to negative.By symmetry, the three other islands have flipped their charge also. Thedaughter substrate is raised over the mother substrate. The two islandsat (5, 4) and (6, 5) repel the island 22-4 b on the daughter substrate.However, the islands at (4, 5), (4, 6) and (5, 6) attract the island22-4 b. By symmetry, the energy barrier surrounding all the cornersislands of the daughter substrate are similar in form and cause thedaughter substrate to start, to rotate in the counter-clockwisedirection 22-9.

FIG. 22 e illustrates the top view 22-10 with the daughter substraterotated 45° as indicated by the current location of island 22-4 b. Thesymbols used on the daughter substrate are changing their relativeorientation due to the rotation of the daughter substrate. Correctionsfor the symbols within the daughter substrate are made in FIG. 22 f. Theisland at (3, 6) is charged positively and is used to help position theisland at 22-4 b after the daughter substrate partially rotates. Oncethe island 22-4 b passes the midpoint of a line drawn between theislands of (3, 5) and (3, 6), the polarity of the charge placed on theisland (3, 6) is flipped to be negative as shown in FIG. 22 f. Thishelps to continue the movement of the island 22-4 b towards itsdestination. In addition, the charge on the island at (2, 5) is flippedfrom a negative to a positive charge; thereby, further encouraging therotation of the daughter substrate since an attractive force is formedbetween the islands 22-4 b and the island at (2, 5). Furthermore, anadditional force is helping to position and rotate the daughtersubstrate by the positive charge of the internal island 22-2 b and thenegative charge of the island at (3, 4).

FIG. 22 g depicts the top view 22-11 of the position of the daughtersubstrate after being rotated 90°. The optional step can be used todischarge the islands that are not responsible for holding the twosubstrates together. The final top level view 22-12 is illustrated inFIG. 22 h and an attractive force is formed at all charged islands thatare juxtaposed to one another. Thus, Coulomb islands if sequenced to becharged properly can be used to lift, rotate, move and drop daughtersubstrates on a mother substrate.

A Laser Interlace System 23-1 (LIS) is illustrated in FIG. 23 a. Thesystem has a mother substrate 23-2 with several daughter substrates onits surface. The list of substrates includes a receiver 23-24, controlunit 23-25, edge emitting laser 23-10, V-groove fiber holders 23-13,laser driver 23-9 and a surface emitting laser 23-3. The control 23-25determines the current positions of the movable substrates, calculatesthe require sequence of movements required to achieve the finalsubstrate configuration, performs the fine tuning the alignment of thefibers to the substrates, and connects the substrates to the mothersubstrate if required. Note that the control unit can also be combinedwith other circuits inside the mother substrate 23-2. Some of thesignals transferring to and from the LIS are optical in nature. Thereceiver 23-24, edge emitting laser 23-10, V-groove fiber holders 23-13,and a surface emitting laser 23-3 are called optical components. Forinstance, 23-21 is an input laser signal for the fiber 23-22 andprovides an optical signal 23-23 to the receiver 23-24, while the outputlaser signal 23-4 emitted from the surface emitting laser 23-3 passesinto the fiber 23-5 and passes the signal 23-6 in the fiber to anotherlocation. The edge emitting laser generates two laser signals 23-11 and23-12 which enter the fibers 23-17 and 23-18, respectively. These twofibers send the signal 23-19 and 23-20 to other locations. Alignmentbetween the core of the optical fiber and the sensor or laser output isrequired to insure maximum power transfer between the two components.The conventional process of making the alignment is complex and mayrequire operator assistance. This is a costly issue and ways of reducingthe cost would be beneficial. Note that due to Coulomb islands andforces the alignment can be done electronically by using controltechniques such as feedback collection using a closed loop. A closedloop feedback system as described in U.S. Pat. No. 5,298,800 can beused. The reason an alignment can be made is because the components canbe positioned by using Coulomb forces. For instance, the moveablecomponents such as the surface emitting laser 23-3 can move laterally asindicated by the two directions 23-7 and 23-8. The orthogonal movement,although not shown, an also occur. Vertical movement such as 23-14 and23-15 are illustrated for the V-groove holder 23-13. In addition,rotational movement is also possible as indicated by the arrow 23-16associated with the V-groove holder. The steps required to perform thesemovements have been described in detail earlier. It is also possible touse MEMS mirrors and place these mirrors between the lasers and thefiber to adjust the laser beam into the fiber.

FIG. 23 b illustrates a flowchart 23-26 to position the laser receiver.The positioning of all the components at a global level was covered inthe flowchart 1-25 shown in FIG. 1 k. The receiver is positioned roughlyas indicated by 23-27. The remaining portion of the flowchart 23-26performs a fine adjustment of the receiver's position to align the fiberto the laser. The sequence of systematic movements is calculated by acontrol chip 23-25 that uses a Finite State Machine (FSM). This sequencecould be as simple as an x-y scan; that is, scan in the positivex-direction, move in the y-direction, scan in the negative x-direction,etc. Check the light in 23-30 and determine if the signal is detected in23-31. If the signal is not detected, lift receiver away from the mothersubstrate 23-33 and move the receiver in one of the portions of thepre-calculated movements 23-34. Drop the receiver to the substrate 23-35and check for light 23-34. If signal is detected, see if signal is at amaximum 23-36. If not, then proceed through the steps 23-33, 23-34,23-35 and determine if level is a maximum. The determination can be doneby matching the position of the receiver with the signal level in amemory, and then the maximum level can be determined by a search of thememory. These positions are applied to the receiver and communication23-37 can occur.

FIG. 23 c depicts another flowchart 23-38 of a control unit thataddresses aligning the V-groove unit to the edge laser. Thedetermination of sequence of movements 23-39 is calculated. Forinstance, movement in the y-z plane can be calculated. Z isperpendicular to the surface of the substrate. Prepare the feedbacksystem to respond to the changes being made 23-40. This requires thereception of a signal from the fiber which is then send back to thecontrol unit to determine optimum operation. Roughly position the edgelaser (flowchart of FIG. 1 k) and turn on laser and emit light 22-42.The fiber is checked for light 23-44, if none found, move the V-groovein one of the sequence steps 22-46. The V-groove is being moved insteadof the laser so the laser can have a solid thermal and electricalcontact with the mother substrate. However, the laser can be movedinstead if a good source of electrical power contacts can be providedand the heat dissipation issue was not a significant problem. An examplegiven previously described the levitation of a daughter substrate withbonding wires attached. Such an arrangement would be able to provide anelectrical power contact for the laser. Once light is detected, the nextstep is to determine if the intensity is at a maximum 23-47. If not,then a systematic movement of steps 22-46 can be performed to maximizethe light. The systematic movement can also comprise steps to tilt orangle the V-groove to improve the intensity. The feedback values arestored in memory along with the physical attributes (x, z, and angle).Once the maximum is located, the attributes can be applied to theV-groove apparatus to position it to the attributes. Then, communication23-48 can occur.

A LoC (Lab on a Chip) 24-1 is illustrated in FIG. 24 a. Fluids 24-11 and24-3 are pushed through pipettes 24-12 and 24-4 to deposit samples 24-13and 24-6. The mother substrate 24-2 can hold several daughtersubstrates, cavities or both. In addition, the daughter substrate canhave cavities, for example, the daughter substrate 24-15 DNA containerand MEMS pump can have at least one cavity 24-14 formed in it. MEMSpumps are used to pump contents between cavities located on the samedaughter substrate or between the daughter, and another daughter or themother substrate. The pumps can extract a certain volume of fluid from acavity or insert a volume of fluid into the cavity. The egress and exitopenings can be fabricated in the daughter substrate and can be locatedon a surface of the daughter substrates, on their edge, or their bottomsurface. The cavity 24-14 can be moved under either pipette 24-12 and24-4 to collect the samples 24-13 or 24-6. Fluids such as; proteins,blood samples, buffers, reagents, and living organisms in liquids inadditional containers or cavities can also be located on differentsubstrates 24-7 and 24-8. For instance, a reagent can be used todetermine protein concentration while buffers can be used to extract DNAfrom whole cells. The pump analyzer 24-17 can rotate 24-20, movelaterally (24-19 and 24-18) and pump contents either from/to a cavity.The analyzer 24-17 can also analyze the fluid for concentrations andother properties. Finally, the vertical motions (24-10 and 24-9) of thedaughter substrate 24-8 can provide additional movements to performsurface properties characteristics and studies. Although not indicated,the 24-8 substrate can contain a pump. The control 24-16 is shown on thesurface of the mother substrate, but can be completely incorporated inthe mother substrate, shared between the mother substrate and each ofthe daughter substrates, shared between a control unit 24-16 and themother substrate or any combination of these. The control unit canreceive its direction from external signals (for instance, passed fromthe PWB (Printed Circuit Board) through the package to the substrates)that exist in external memory or can be calculated on the fly by aninternal/external processor.

A cavity is filled with a fluid when the forces due to the mass of thefluid just equal the forces holding the surface together. In thiscondition, the surface tension can generate two different contact angles(θ₁ and θ₂) as depicted in FIG. 24 b. Once the contact angle is greaterthan 90°, the fluid can overhang the substrate as illustrated by thedrop 24-24 where the contact angle is θ₁ in FIG. 24 b. The shape of thedrop for a contact angle less than 90° is shown by the drop 24-23 withan angle of θ₂. FIG. 24 c illustrating a cross sectional view 24-25 of aLoC system. Some of the cavities on the daughter substrates can befilled with fluids and form a variety of contact angles with thesubstrate. These cavities can be formed near the edge of the substratesuch that the contact angle is greater man 90° and causes the liquid tooverhang the substrate. The mother substrate 24-26 is under thelevitated daughter substrates 24-27 through 24-30, each having at leastone cavity 24-31 through 24-34, and each having a drop of fluid 24-35through 24-38, respectively. All of the drops have a contact anglegreater than 90°.

In FIG. 24 c the daughter substrates 24-29 and 24-30 are moved close toeach other using the Coulomb force due to the Coulomb islands until theoverhangs touch each other 24-39. Note that the daughter substrate 24-29is not in contact with the daughter substrate 24-30. The control unit(not shown) determines the procedure of charging the Coulomb islands tomove the daughter substrates so the daughter substrates perform therequired moving actions. In addition, the control unit may performadditional steps; applying voltage potentials across the common surface,measuring the current that flows between fluids, adjusting theconcentration of the fluids, etc.

Once the contact is made several studies can be carried out. Thesurfaces of the liquids are now in contact and studies may be conductedon the surface properties of these two liquids to determine if diffusionbetween the fluids occurs even if the surfaces are not broken. Thissubstrate arrangement offers the ability to study the characteristicsof: 1) surface features of the same or different fluids whose surfacesare placed in contact with one another; 2) potentials can be applied toeach fluid to study the transfer of charged ion components between thefluids; 3) using a pump, some of the fluid can be extracted thenadditives can be added to either fluid to see how changing thecharacteristics of the fluid affects either the solution or the surfaceproperties; 4) using the pump, samples of the fluid can be extracted andanalyzed to determine its properties: 5) one substrate can be movedlaterally to rub the surfaces together to determine a “coefficient offriction”; and 6) to determine when and if the surfaces breaks and underwhat force was required to do so. FIG. 24 d illustrates another crosssectional view 24-40 where a drop with a contact angle greater than 90°can be placed in contact with a drop having a contact angle less than90° as shown by the contact point 24-41. The substrates can be connectedto the mother substrate and a current 24-43 can be forced to flow fromone drop to another. Another test is just applying a potentialdifference between the two drops in contact. Some of these tests requirea microscope and human observations while others can be performedentirely by the control unit.

FIG. 24 e provides a flowchart 24-44 for positioning the pipette anddropping samples into cavities. As the pipette gets close to asubstrate, capacitances are used to determine their distance andposition. The capacitor can be formed between the tip of the pipette andthe cavity. The first step is to determine a sequence of movements toplace cavities under the pipettes 24-45. Pick the first recipient 24-46and determine if recipient is in the right position 24-48. Moverecipient until it is positioned correctly 24-49. Determine if thepipette is over the cavity 24-51, if not, position the cavity better24-52. Otherwise, drop a sample from the pipette into the cavity 24-53.Determine if there are more cavities in recipient 24-54, if there aredetermine next cavity and go to 24-48 and repeat previous steps,otherwise determine if there are more recipients 24-56, if there aremove to next recipient 24-57 and select cavity, place cavity in position24-48 and repeat previous instructions, otherwise samples are preparedfor experiment 24-58.

As the containers are moved, capacitances are used to determine thendistance and position. FIG. 24 f provides a flowchart 24-59 forpositioning the container and pumping samples into/out-of cavities inthe mother substrate. A sequence of moves 24-60 is determined by acontrol unit. Note that another possibility is to calculate a portion ofthe steps required to position the containers and determine the rest ofthe movements on the fly. Then the first step is to move a container tothe carrier cavity 24-61. Is the desired portion of the container overthe cavity 24-63? If not, move the container until it is closer 24-64.The desired portion of the container can have a hole drilled through thedaughter substrate such that the hole overlays the cavity. Then a pumpcan force the reagents/buffer/fluids into the cavity 24-65 through thehole in the substrate. Check to see if there are otherfluids/reagents/buffers that need to be added 24-66, if so, go to nextcontainer 24-67 and repeat steps for pumping. Otherwise, performoperation 24-68 which may include heating, mixing, vibrating, etc, thenpump contents into the analyzer 24-69, analyze the contents 24-70 andcommunicate results to user 24-71.

FIG. 25 illustrates the movement of a grand daughter inductor that canmove over daughter substrates. The first position of the substrates 25-1are shown in FIG. 25 a. The mother substrate 25-2 has three substratesdirectly on it; memory 25-10, microprocessor 25-6 and an auxiliarysubstrate 25-5. Then, two grand daughters 25-3 and 25-4 are place on thedaughter substrates 25-6 and 25-5. The grand daughters are inductors andcan be used by the microprocessor 25-6 in a PPL (Phase Lock Loop) or LCtank circuit to generate a clock signal. Changing the inductors changesthe frequency range of oscillations of the PLL. Note that a granddaughter substrate can span over two daughters simultaneously as shownin FIGS. 25 a and 25 d. One possible advantage is that themicroprocessor 25-6 may not require the Coulomb islands at all if mostof the inductor overlaps the other daughter substrate 25-5. Thesubstrates 25-5 and 25-4 would have the coulomb islands and they wouldbe designed to support the entire inductor substrate 25-4 even if aportion of the inductor substrate is overhanging. This overhang portionwould have at least two electrical contacts for each lead of theinductor substrate 25-4 and would overlap the microprocessor 25-6 tomate with its exposed electrical posts to complete the PLL circuit. Ifthe second inductor is desired to change a frequency of operation, theremaining Figures depict how the two inductor substrates can be swapped.The first step is to lift and move the first inductor substrate 25-4 inthe direction 25-7 to the location shown in 25-8, then as illustrated inFIG. 25 b move 25-4 in the direction 25-9. Once the first inductorsubstrate 25-4 provides an opening for the second inductor substrate25-3 as shown in 25-11, move 25-3 in the direction 25-12 until theinductor substrate 25-3 arrives in the position shown in 25-13 of FIG.25 d. Once the inductor substrate has its electrical contacts alignedover the posts, the inductor is dropped to make electrical contact. Notethat the substrates 25-5 and 25-6 remained stationary when the inductorwas exchanged.

In some cases of exchange, both the daughter and grand daughtersubstrates can move simultaneously to make exchanges. This addscomplexity to the control of the system since the grand daughtersubstrate moves with respect to the daughter substrate while thedaughter substrate moves with respect to the mother substrate. The paththat the grand daughter sweeps out with respect to the mother substratecan be quite complex. However, in some cases, such a path can providequicker reassembly, lower power dissipation, construction of an unusualdesign, or some other cost function. The control unit can be programmedto select the appropriate algorithm to perform the required moves forthe given cost function.

FIG. 26 a depicts an accelerometer 26-1 that can detect a lateral andvertical acceleration or deceleration. The structure comprises a mothersubstrate 26-4 with capacitor plates (26-5 and 26-6) while the remainingcomponents shown are charged Coulomb islands. The daughter substrate26-3 with capacitor plates (26-7 and 26-8) while the remainingcomponents shown are charged Coulomb islands. Note that the lowerCoulomb islands in 26-4 can have a different width than those found in26-3. This will offer the movement of the daughter substrate with: 1) amore controlled height vs. displacement; and 2) offer more elasticity tothe movement of the upper substrate since the forces from the lowersubstrate are spread out over a larger area thereby equalizing the forcebetween the two juxtaposed islands over short distances. A top view 26-9of the metallic capacitor is depicted in FIG. 26 b which is the viewfrom 26-2 of FIG. 26 a. The letter endings of M and D correspond to theMother and Daughter substrates, respectively. The first capacitancebetween the capacitor plates 26-5M and 26-7D can be measured andcompared with the second capacitance of the capacitor plates 26-8D and26-6M. In addition, these values can be compared with the system at restor at the equilibrium position. The first and second capacitance shouldapproximately be equal at the equilibrium position.

In FIG. 26 c, the upper Coulomb islands 26-11 and 26-12 are negativelycharged, while the lower islands 26-13 and 26-14 are charged positivelyand negatively, respectively. The islands 26-11 and 26-13 attract whilethe island 26-12 and 26-14 repel. The widths of the islands werediscussed previously. Now assume that the system 26-10 is quicklyaccelerated to the right. This causes the daughter substrate to lag themother substrate as shown in FIG. 26 c. The lag 26-15 causes the uppercapacitor plates to shift with respect to the lower capacitor plates.For example, the distance 26-16 is less than the distance 26-17; thus,the capacitance of the two pair of capacitors (26-7 and 26-5; 26-8 and26-6) can be calculated to determine the direction and acceleration ofthe system. The top view 26-9 of the capacitor plates are illustrated inFIG. 26 d. One can visually see displacement. By measuring the time andlag (by capacitive techniques) between the two sets of capacitor plates,and knowing the mass of 26-3, all Coulomb forces, distance of substrateseparation, mass of daughter substrate, the velocity and accelerationcan be determined.

The accelerometer 26-1 in FIG. 26 a can optimally detect lateral motionin one direction of the two orthogonal directions. FIG. 27 a reveals theprevious plate structure to defect motion in either/or both orthogonaldirections. The detection of movement in the orthogonal directionrequires the use of additional capacitors plates that are orthogonal tothe first set. These additional capacitor plates are labeled in the topview 27-2 of FIG. 27 b. The capacitor plate pairs are: 27-5D and 27-3M,27-6D and 27-4M. Note that when the daughter substrate moves to theleft, the capacitance of these two pairs of capacitor change in the sameway. Thus, the electrical measurement of all four capacitors can bedetermined and applied to a FSM to calculate which direction thede/acceleration is occurring. Note also that accelerations in thevertical direction can also be determined since the capacitance of thecapacitors will decrease/increase as the daughter substrate movesaway/towards the mother substrate.

Other forms of capacitors that are useful to detect acceleration areillustrated in FIGS. 27 c and 27 d. A single lead-multi lead capacitor27-7 shows the circle 27-8 on the top substrate while the individualmetal strips 27-9, 27-10, 27-11, 27-12, 27-13, and the remaining stripsaround the

FIG. 28 a depicts a block diagram 28-1 of a movable system (e.g.automobile) with a deceleration device 28-2 which feeds information to aFSM (a DSP 28-3 is shown, but it could be a microcontroller, ASIC, FPGA,microprocessor, etc.) to be processed. The result is applied to the bus28-5 and is applied to the airbags (AB) 28-4 and determines theappropriate AB's to fire and their tiling sequence to minimize bodilyinjury due to the impact of the crash.

FIG. 28 b illustrates the flowchart for an accelerometer which uses thelevitated substrate and Coulomb islands as described earlier. Such anaccelerometer may be useful in any moving vehicle. Assume the system isat rest, then go to start 28-8, measure the capacitance 28-9 (forexample, the capacitance 26-5M and 26-7D) and in a loop continuemeasuring the capacitance until a change is noted. From the displacementof the daughter substrate determine the lateral (or horizontal) movement28-11, then determine the direction of the acceleration or deceleration28-12. Next check if the vertical capacitors have changed 28-13, if so,measure the vertical distances 28-14, then use these values to determinethe vertical acceleration or deceleration 28-15, once all data isavailable report, or store the information to the system 28-17.

FIG. 29 a depicts a view 29-1 of a two layered system on mothersubstrate 29-2 containing a daughter and grand daughter layer. Thedaughter layer comprises: the FPGA 29-14, Microprocessor 29-12, DSP 29-5and Video Accelerator 29-8; and memory substrates 29-6, 29-16, 29-10 and29-3. The grand daughter layer comprise: the connect substrates 29-13,29-11, 29-9, 29-4 and 29-17; and the capacitance substrates 29-15 and29-7. The connect substrates can have many uses; one is to bypass theoutput/input buffers of a path connecting the core of one substrate withanother, another is to electrically connect metal segments of adjacentsubstrates together. FIG. 29 b illustrates a cross sectional view 29-18of how the bypass is made, see U.S. Pat. Nos. 6,465,336 and 6,281,590.The cross section is that of the video accelerator 29-8, the connectsubstrate 29-9 and the memory 29-3. The video accelerator has a core andwould conventionally receive data received from the I/O pad 29-20 afterpassing through the input buffer 29-23. The I/O pad can be wire bondedor solder bumped. The input buffer has a delay or consumes time. Thememory substrate 29-3 has the M-core and conventionally applies data tothe output buffer 29-19 which drives the I/O pad 29-20 and drives a lowimpedance environment (50Ω) of the package and PWB boards. This requiresa large width transistor to apply a signal into this environment and cangenerate a large amount of switching noise due to the parasitic elementenvironment The output buffer also consumes time. To overcome the delayand noise issues, the connect substrate 29-9 can be used to tap into theinternal path between the core and the I/O. These internal tap pointsare connected to the posts 29-21 and 29-22 and are called as I/O ports.The connect substrate 29-9 has post 29-21 a and 29-22 a that are shortedby a metallic path. The posts 29-21 a and 29-22 a make contact with theposts 29-21 and 29-22, respectively. Thus, the I/O components 29-23,29-20 and 29-19 are bypassed eliminating their delay, noise and powerdissipation. FIG. 29 c depicts a cross sectional view 29-24 of acapacitor substrate 29-26 that connects to a lower substrate chip 29-25which is being moved across the substrate 29-25 over the surface of amother substrate. The capacitor substrate has been charged to the powersupply, connects to the daughter substrate and can serve as an auxiliarypower supply while the daughter substrate is activating its Coulombislands to perform movements on the mother substrate. Because thecharging and discharging of the Coulomb islands could use power, acapacitor substrate 29-26 rides on the daughter substrate and acts as atemporary power supply as the energy in the charged capacitor 29-27 isused, for example, see US app 20060122504. One side of the capacitor isconnected to the power supply of the lower substrate through the posts29-28 and 29-29. Similarly the other side is also connected by connectedposts. The energy stored in the capacitor 29-27 can be used to allow thelower substrate 29-25 to levitate for a longer time period. Although notshown, a DC voltage regulator may be requires to maintain a constantvoltage applied to the daughter substrate. When the capacitor is notused, it can be charged by being connected to a

As RF frequencies continue to increase in carrier frequency, thewavelength continues to decrease. The antenna used to capture thissignal is of finite size and has a relationship to the wavelength. Whenthe antenna dimensions are as follows:

ka<1   (7)

where

${k = \frac{2\pi}{\lambda}},$

“a” is the radius a sphere enclosing the antenna, and λ is thewavelength. Then, the antenna is an Electrically Small Antenna (ESA) ifthe condition in Equ. 7 is satisfied. The ESA determines the impedancebandwidth of an antenna and the Q of the antenna. These antennas willhave a lower Q.

Various frequencies are allowed for communications. The PersonalCommunication System (PCS) operates at 1900 MHz, Global PositioningSatellite (GPS) is at 1,500 MHz , and GSM (Global System for Mobilecommunications) at 900 MHz. The wavelength ranges from 16 to 33centimeters. Forming an antenna on a substrate with a side dimension of1 cm and using Equ. 7 would indicate that the antenna would be an ESA.

The FCC (Federal Communications Commission) has adopted rules for 71-76GHz, 81-86 GHz and 92-95 GHz bands. The wavelength of the earner wouldbe approximately range from 3000 to 4000 micrometers. Depending on thefinal antenna design and layout, the ESA conditions are not as prevalentas they were for the PCS, GPS and GSM systems. An antenna has an optimalperformance when the antenna is designed for a given frequency. As thecarrier frequency changes, the transfer power of the captured signal inthe antenna to the RF frond end decreases. An ideal way of overcomingthis issue is to reconfigure the dimensions of the antenna so that theyoperate as a function of the carrier frequency. Another way is toreconfigure the dimensions of the antenna so that they operate withinthe center of each of the three FCC bands. The dimensions of the antennacan be redesigned on the fly using Coulomb islands. For instance, FIG.30 a illustrates a block diagram 30-1 of an RF front end 30-4 driving adipole antenna composed of two legs 30-2 and 30-3. The length of eachleg is related to the carrier frequency given earlier. Since thesedimensions are in the range of thousands of micrometers, the adjustmentsto the length of the antenna can be done on a conventional CMOSsubstrate.

FIG. 30 b illustrates a Reconfigurable Antenna on a Substrate (RAS)30-5. The mother substrate 30-6 carries a portion of the radio circuitry(RF Front End 30-4) closest to the antenna that is concerned withreceiving/transmitting signals from/to the antenna, respectively. Inaddition, there are a multitude of substrates with a variety of shapesin the metallic layers that can be reconfigured as antennas. Theindividual antenna substrates currently appear to be similar but can beof any required size and shape to satisfy the designs goals. Although, adipole will be described, this invention can be used to modify thedimensions of: a) a patch antenna to λ/2 and control the height of thepatch above a ground plane on the mother substrate, b) MIMO(Multiple-input Multiple-output) antennas, c) Yagi antenna, and 4)reflector based antennas to name a few. The RF Front End 30-4 can beconnected through the mother substrate 30-6 to the antenna substrates30-7 and 30-11 which form one end of the dipole antennas 30-2 and 30-3.The antenna substrates 30-7 through 30-10 are connected to each other toform the leg 30-2 of the dipole, while the antenna substrates 30-11through 30-14 form the leg 30-3 of the dipole.

The antenna substrate can be: 1) connected to the adjacent antennasubstrate by using the “connect substrate” discussed in FIG. 29 b; 2)dropped and connected to the mother substrate and the mother substratecompletes the connection; and 3) physically abutting the exposed metalfeatures along an edge of both antenna substrates together, allowing ahorizontal connection to be made between the two antenna substrates(this will be covered in detail shortly). With regards to the thirdpoint, Coulomb islands can be formed in the edge of the substrate aswill be described shortly. The Coulomb forces can be used to hold theantenna substrates together.

FIG. 30 c illustrates the case where the carrier frequency has increasedthereby requiring the dipole to be shortened. Both legs of the dipole30-18 and 30-19 need to be decreased in length. FIG. 30 d illustratesthe final placement of the antenna substrates 30-10 and 30-14 after theywere moved into then final position. Thus, the length of the legs of thedipoles 30-18 and 30-19 were decreased by moving the antenna substrates30-10 and 30-14 away from the active dipole. These substrates were movedusing Coulomb forces and placed next to the antenna substrates 30-16 and30-15 respectively. Note that these extra antenna substrates can bere-positioned to make a reflector branch in the overall antenna if sodesired. The reconfigurabilty of the system allows the antennas toadjust themselves as the conditions applied to the system vary. Thisallows radiation patterns, impedance bandwidths, operating frequency andpower transfer conditions to be controlled and adjusted wheneverrequired.

FIG. 31 a reveals a Yagi antenna 31-1 connected to the RF front end31-4. The Yagi antenna has a pair of reflectors 31-2, the active dipoleantenna pan 31-3, and the directive antenna 31-5. This antenna systemhas been re-configured and optimized to operate at a given carrierfrequency in FIG. 31 b where the groupings of the metallic substrateshave the same identification number as given in FIG. 31 a. Several rowsof metallic strips are illustrated on the mother substrate 31-7 of theantenna system 31-6. The director 31-5 is comprised of 9 metallicsubstrates connected together, the dipole is comprised of the set of 4metallic substrates connected together 31-3 on each side and thereflector is formed by the pair of grouping 3-2. The extra metallicsubstrates are in the groupings 31-8 and 3-9. The Yagi antenna can bereconfigured as a function of carrier frequency, increasing the numberof director and/or reflectors.

A patch antenna 31-11 connected to an RF front end 31-4 is shown in theblock diagram 31-10 in FIG. 31 e. The physical realization 31-12 isgiven in FIG. 31 d. The patch antenna is comprised the 4×4 metallicsubstrate array 31-11. This array can be moved up 31-13 and down 31-14to space the array from the ground plane to help match the impedancebandwidth. The length of the array 31-17 reconfigured to be set to beapproximately λ/2. The extra metallic substrates are in the groupings31-15 and 31-16. Note that this substrate could be used to create MIMOantennas by insuring that the front end 31-4 can accept severalinput/output antenna ports. Further more, depending on the size of themother substrate 31-7 and the total number of metallic daughtersubstrates, separate antennas designed for outgoing frequencies can bereconfigured at the same time other separate antenna are beingreconfigured for different incoming frequencies. Thus, thisreconfigurable antenna system can be very diverse and offers greatflexibility to the system designer by offering on the fly antennaadjustment capabilities.

An issue important to communications is the interception of orthogonalsignals. Typically, orthogonal surface planes containing the antenna arebeneficial. Reconfigurable techniques can be use to implement antenna onsurfaces which are orthogonal to each other. The following diagram helpsexplain the inventive technique to achieve this capability. FIG. 32 adepicts a cross sectional view 32-1 of three substrates; 32-2, 32-3 and32-4. The substrates 32-2 and 32-3 are connected together by waferbonding, for example, to form the 32-5 substrate. Assume that thesubstrate 32-5 is firmly attached to a stable support. Thus, Coulombforces will be used to manipulate the substrate 32-4 and move thissubstrate in the 32-6 direction. Note the charges on the commonjuxtaposed islands can be modified to control movement as coveredearlier. The cross sectional view 32-7 in FIG. 32 b illustrates thesubstrate 32-4 moved one unit to the left and the islands charged tocause a rotation of the substrate 32-4 in the direction 32-9. Theislands 32-9 a and 32-9 b repel one another to place a torque on thesubstrate 32-4. The islands to their immediate left are attractive toeach other and in addition, the group of positive islands 32-6 agenerates an induced charge on the side surface of the 32-5 substrate.The induced charge 32-8 formed at the edge of the substrate 32-5 isnegative and attracts the charged islands at 32-6 a. These two laterattractive forces prevent the substrate 32-4 from detaching and fallingoff the substrate 32-5 and furthermore increase the torque on thesubstrate 32-4.

FIG. 32 c reveals the net forces applied to the system 32-10 to create arotation 32-9 of the substrate 32-4. The gravitational force 32-11 mustbe stabilized and overcome by the forces generated by the induced andisland charges. The set of unit vector's forces 32-13 are used toprovide torque to the end of the substrate. The grouping of unit vectorforces 32-12 help to maintain cohesion of the substrate 32-4 to thesubstrate 32-5 near the pivot point. The group of unit vector forces32-14 caused by the induced charges help to pull the substrate 32-4towards the edge of substrate 32-5, while the vector 32-15 pulls in thesame direction.

Induced charges at the edge of the substrate helps to pull the daughtersubstrate toward the edge of the mother substrate 32-5 as indicated bythe unit vector forces 32-14. Induced charges can also be used as anattractive force while the daughter substrate moves over the surface ofthe mother substrate. This has not been described in detail but thebasic concept of induced force can be visualized in FIG. 3 c. As thenegatively charged external plate 3-8 approaches the Coulomb island 3-5,the positive induced charges in the Coulomb island will attract theexternal plate. Thus, this Coulomb force can be used when an attractiveforce is desired.

Also in place of the induced charges being formed on the edge of thesubstrate to help attract the daughter substrate 32-4, edge Coulombislands can be used to attract the daughter substrate. In addition, acorner substrate can be placed flush with the edge of the substrate 32-5to provide support, additional Coulomb islands and surface area. Morewill be stated about the “edge Coulomb island” and the “cornersubstrate” shortly.

FIG. 32 d shows the cross sectional view 32-16 where the substrate 32-4is positioned orthogonal to the substrate 32-5. To lock the substrate inposition, the second island from the top of substrate 32-4 shouldreverse the negative charge to a positive one. This would cause the unitvector force 32-19 to change from repelling to attractive which wouldlock the orthogonal substrate in place. The description of how adaughter substrate can be rotated around the edge of a mother substratehas been given.

However, if the substrate was desired to be moved to the bottom of thesubstrate 32-5 then the repelling charge that generates the unit vectorforces 32-19 can be used to continue the rotation 32-9 around thesubstrate 32-5. FIG. 32 e illustrates this rotation where only the unitvector forces 32-21 are shown. These forces enable the rotation andplace the substrate 32-4 on the bottom of the substrate 32-5. Thegravitational force 32-11 applied to the substrate 32-4 needs to becompensated for by the Coulomb forces. Furthermore, addition Coulombforces are required to insure that the substrate 32-4 is pulled to thesubstrate 32-5. In some situations, the mass of the substrate 32-4 mayneed to be reduced by back grinding the foundation portion of thesubstrate. This can reduce the gravitational force 32-11 and allows theCoulomb forces to dominate the gravitational force. The last step ofplacing the substrate 32-4 on bottom of the substrate 32-5 is not shownsince it is straight forward by applying the previous rules given inthis specification.

An aspect that has not been used previously in the design of systems isusing the edge of the substrate to perform connectivity functions. FIG.33 b reveals the cross sectional view of the edge of the substrate 33-16before edge processing. This substrate was cut apart from the waferusing a saw. The action of the saw can chip pieces off the edge of thesubstrate. The edge of the substrate can be polished until the edge ofthe substrate appears as shown in FIG. 33 b. Then further processingsteps can be used to cut back the foundation and component portions 2-2,2-4 a and 2-4 b of the substrate until a distance 33-17 is removed (wetetch, plasma etch, etc). This process exposes the metal trace/via stack33-2 where the metal stands out against the background of the oxidemaking this contact appears as a metallic post. However, the metaltrace/via stack 33-3 is still encapsulated in oxide because thismetallic stack was set back further from the edge of the substrate thanthe metal trace/via stack 33-2. The metal trace/via stack will bereferred to a “metallic stack.” FIG. 33 a illustrates a cross sectionalview 33-1 of a substrate 33-13 that has been processed on the edge toexpose a portion of the metallic stack 33-2. The metallic stack 33-2 isexposed on its left side and a portion of the back and front of thestack 33-2 is also exposed. Note that the metallic stack 33-3 is stillcompletely surrounded by an oxide layer. The metallic stack 33-2comprises the metal layers 33-6 through 33-12 while the metallic stack33-3 comprises the metal layers 33-6 through 33-10. In addition, thecomponent portions can have Coulomb islands 33-4 and 33-6 and electricalcontacts 33-5. The exposed metal trace/via stack comprising the metallayers 33-6 through 33-12 is also known as an I/O (input/Output)connection, and serves in part the same function as an I/O pad that isfound on the surface of a conventional substrate which is to allow theentrance and egress of signals and power.

There are several differences between the I/O connection and the I/Opad, however: 1) the I/O pad is parallel to the surface of the substratewhile the I/O connection is perpendicular to the surface; 2) a singleI/O connection can have minimum dimension of in the range of onemicrometer while a conventional I/O pad has a minimum dimension of 50 to100 micrometers; thus, the packing density of the I/O connection isorders of magnitude greater than the conventional I/O pad; and 3)current can flow horizontal with respect to the substrate in I/Oconnection while the current flows vertically in the I/O pad. Theelectrical contacts 33-5 is also known as the I/O port, and serves inpart the same function as an I/O pad that is found on the surface of aconventional substrate which is to allow the entrance and egress ofsignals and power.

There is at least one difference between the I/O port and the I/O pad,however: a single I/O port can have minimum dimension in the range ofone micrometer while a conventional I/O pad has a minimum dimension of50 to 100 micrometers; thus, the packing density of the I/O port can beorders of magnitude greater than the conventional I/O pad. The minimumdimensions of 50 to 100 micrometers for an I/O pad is derived themechanical tolerances of connecting the substrates in a package by usingsolder bumps connection or wire bonding procedures, respectively.

Note that, as done previously, any electrical connections to themetallic stacks, the Coulomb islands or the electrical contacts are notshown and have been removed to simplify the diagram. It should beunderstood that the electrical connections can be capacitive, resistive,inductive or any combination of these. The substrate 33-13 could beformed by wafer bonding two substrates back to back, although asdescribed earlier, there are many equivalent alternatives possible.

The top view 33-14 indicated in FIG. 33 a is shown in FIG. 33 e. Notethe exposed metallic stack 33-2 along with the two insulated Coulombislands 33-3 and 33-18 on each side of the metallic 33-2 stack. TheCoulomb islands 33-3 and 33-18 and the exposed metallic stack arepresented in FIG. 33 d from a different perspective. This figurecorresponds to the view 33-15 indicated by the arrow of FIG. 33 a. Thetwo vertical metallic stacks 33-18 and 33-3 form edge Coulomb islandsand can be used to create attractive Coulomb forces to hold the edge ofthe substrate 33-13 against a second substrate. These two verticalmetallic stacks form two metallic planar surfaces, albeit these surfacescan be perforated due to the gaps between the traces. These edge Coulombislands that are formed from the two metallic planar surfaces areperpendicular to the surface of the substrate. Meanwhile the exposedmetallic stack can make an electrical connection with an exposedmetallic stack on the second substrate. These stacks are composed ofparallel metallic traces connected by vias also form metallic planarsurfaces. The area of the exposed metal layered structure can beproportional to the amount of current being carried.

Note several conditions with these vertical “planes”: 1) the metal andvia layers 33-6 through 33-12 and the metal and via layers 33-6 through33-10 are used to form the three independent vertical planar metallicsheets (of course, it is not necessary to use all metal trace/vialayers); 2) the position of the metal to the edge of the substrate isdetermined by the layout (positioning) of the metal layers and CAD(Computer Aided Design) layout tools can be used to automatically placethese layers; 3) the connectivity can be either capacitive, resistive orinductive; and 4) they can be used as a edge Coulomb island, an edgecontact or one of the plates of an edge capacitor.

FIG. 34 a depicts the top view 34-1 of two substrates 34-2 and 34-3connected at then edges. The attractive force generated by the two pairof edge Coulomb islands: 34-6 and 34-7: and 34-8 and 34-10 are used tohold the two substrates together along their edges. The metal extensions34-4 and 34-5 or edge contacts are forced into each other at the commoninterface 34-15 and can be used as an electrical contact. The rightsubstrate 34-3 has an electrical contact 34-16 that exits the bottom ofthe substrate 34-3. In addition, the metal trace 34-17 connects theelectrical contact 34-4 to the metal extension 34-18. The regionslabeled 34-9 can be used as electrical contacts or as Coulomb islands.FIG. 34 b illustrates the side view along the dotted line 34-19 in FIG.34 a. The electrical contact 34-16 is connected to the metallic stack34-21 (note that the upper portion of the stack is not partitioned intometal trace/via layers for simplicity). The substrate through via 34-23provides an ohmic contact through the foundation portion 2-2 and allowsthe I/O port to connect to the metallic stack 34-21. The stack 34-21connects to the metal trace 34-17 which then connects to the metalextension 34-5. The Coulomb force connects the two metal extensions 34-5and 34-4 which is connected to the metal trace 34-18 within thesubstrate. Any metal level can be used form the metal trace within thesubstrate and the metal trace can be formed into various shapes usingthe allowable processing steps. These shapes can be used to forminductors, antenna sections, capacitors or interconnect. The Coulombislands 34-11 through 34-14 are shown charged positively.

Orthogonal antenna configurations are an important capability forcomplex antenna systems. An antenna picks up signals from a transmittertypically after the signals have been reflected from various surfaces.Thus, the complete incoming signal composed of signals that are delayed,polarized in different orientations, arriving from different directions,and of course decreased in magnitude. The difficulty is the developmentof nulls in the radio spectrum that decreases the intensity of theinformation. If an antenna with a given polarization is placed right atthis point then the signal intensity can be lost. The other twopolarizations associated with this radio spectrum may have signalintensity at tins point; but the antenna unfortunately is not equippedto capture these signals. Ideally, the complete antennas should havethree antennas that are orthogonal to each other. Several reasons haveprevented this from being standard equipment: 1) the cost ofmanufacturing the equipment; 2) the volume displaced to enable theseantennas (covering three orthogonal directions); and 3) the need forthree antenna ports on the front end or the ability to easily switchbetween the three antennas. As carrier frequencies increase, thewavelength of the carrier decreases. At 75 GHz, the wavelength of thecarrier is comparable to the dimensions of the substrate allowing theformation of the antennas on the substrate. However, the invention isnot limited to these high frequencies. At lower frequencies: PCS, GPSand GSM, Equ. 7 indicates that the condition will be met and the antennawould be an ESA making the design of the communication system withregards to the front end more difficult.

MIMO can benefit from this technique as well since MIMO operates on asingle signal that is sent on (n) multiple antennas such that each ofthe (n) signals received have traveled different paths. MIMO radio usen-antennas simultaneously to extract the n-signals and combine then-signal energies that are related.

An orthogonal antenna system can intercept signals in very diversepolarizations. A three way orthogonal antenna can be designed to captureinformation from three different planes, which allows this technique theability to capture more energy. FIG. 35 a shows a 2D view withperspective 35-1 of a mother substrate 35-2 with a plurality of daughtersubstrates. The antenna substrates 35-3 through 35-8 combine severaldaughter substrates held together using edge Coulomb forces to generateantenna substrates that have metal patterned shapes appropriate for theformation of a variety of antennas. The entire area of the antennasubstrate may be: 1) covered with metal; 2) covered with strips of metalto form a portion of a dipole, reflector or director antenna: or 3)partitioned into two or more separate antennas (for instance, the threeantenna 35-16 or 35-17 shown as dotted arrows on the antenna substrates35-7 and 35-8, respectively) where each of the separate antennas canhave a separate electrical feed to the mother substrate. An example of asubstrate that can be used as an antenna substrate which has a metaltrace is shown in FIG. 39 b. The antenna substrates can be coupledtogether to form metal layers that form patch, Yagi, monopole, dipole,bow-tie, meanderline, MIMO, and a variety of other antennas to becreated. Many of these patterns can be reconfigured to fit differentantenna specifications. Antenna substrates 35-5 through 35-8 are rotatedin the direction shown until these substrates have planar surfacesperpendicular to the surface of the mother substrate 35-2.

FIG. 35 b shows the system 35-10 after these antennas were rotated 90°around the edge of the mother substrate 35-2 and held in place asdescribed in the previous diagrams given in FIG. 32. The mothersubstrate is held firmly in place (not shown). The three pair ofantennas: 35-4 and 35-3; 35-5 and 35-6; and 35-7 and 35-8 are orthogonalto the other two pairs. Compare the orientation of the antennasubstrates with the Cartesian coordinate axis shown above. Each of thepair of antennas can be configured to be one or more antennas where eachone can comprise a: 1) dipole antenna; 2) patch antenna; 3) a set ofMIMO antennas having the same or orthogonal orientations; or 4) any ofthe previous mentioned antennas. One of each pair of antennas cantransmit signals at a given frequency while the other pair can receivesignals at a different frequency. One of the pair of the antennas cancontain several antennas at the same orientation 35-16 while theremaining pair of the antennas can have a 90° rotation orientation 35-17as in antennas 37-7 and 35-8. In this case, a single flip around oneedge of the substrate creates three antennas that are each orthogonal tothe other two antennas. The transmit/receive signals are processed bythe RF front end 35-9. The number of antenna/s that can be used can varyfrom 1 to n. The substrates 35-11 through 35-15 can be used to sentsignals from either the top or bottom surface of its substrate and sendthese signals out of the edge of its substrate (These substrates can becalled “corner substrates” since they push signals around the corner ofa substrate.). The signal passes horizontally between the substrate35-11 and the antenna substrate 35-5, for example. Vertical Coulombislands can formed on the edges of the substrates 35-11 through 35-15.The substrate 35-11 can apply a Coulomb force to the antenna substrate35-5 so that the substrate 35-11 can provide metallic connection to theantenna. In addition, a more rigid support is formed for the antennasubstrate 35-5.

The antennas: 35-4 and 35-3; 35-5 and 35-6; and 35-7 and 35-8 can beflipped back onto the mother substrate and can be reconfigured for adifferent carrier frequency. Once the replaced substrates arereconfigured, the Coulomb force formed at the edge of the substrate canbe used to hold these smaller substrates together to form the largersubstrates: 35-4 and 35-3; 35-5 and 35-6; and 35-7 and 33-8. Then, thelatter two pairs can be flipped 90 with respect to the mother substrateand mounted on the edge of the mother substrate again.

FIG. 36 illustrates an interconnect system 36-1 comprised of severalsubstrate: 36-2 through 36-5. The substrates 36-2 and 36-4 showconnections through their top surfaces only. The substrates 36-5 and36-9 are connected together by Coulomb forces. Note that there is a gap36-22 between the edges of the substrates 36-5 and 36-9. The region36-23 is not shown in detail but contains a plurality of pairs ofCoulomb islands that hold the two substrates together. A substrate thatis normal to the page can be inserted into the gap 36-22 and connectedto the contacts by the Coulomb island to the substrate 36-9 so theinterconnect system can be constructed in 3-D. The substrate of 36-5shows connections only along its edges while the substrate of 36-9 showsconnections through either the edge or top surface (see I/O port 36-11)of the substrate. Substrate 36-3 shows connections through either theedge or top surfaces.

The inner substrates 36-3, 36-9 and 36-5 form several layers ofsubstrates. One of the problems of vertical stacking of substrates isthe difficulty of sending power and signals between the various layers.The two side substrates 36-2 and 36-4 illustrate how the power andsignals can transfer between the various layers of the substrates. Thesehave the metallic traces inside the component portion 2-4 of thesubstrate are indicated by the dotted ellipses 36-6 and 36-7. Thesubstrate 36-2 connects the lower substrate of 36-5 to the top mostsubstrate 36-3, while the substrate 36-4 connects the lower substrate of36-5 to the upper substrate of 36-5.

The substrates are moved into and held in position by using Coulombforces generated by the Coulomb islands. The process of moving andholding the substrates into position has been covered in previousparagraphs. For example, the Coulomb islands 36-12 and 36-17 attract theislands 36-14 and 36-8, respectively. Note that the Coulomb island 36-12is parallel to the top surface of the substrate 36-2; so this island canalso be called a “surface Coulomb island.” The Coulomb island 36-14 isparallel to the edge of the substrate 36-3; so this island can also becalled a “edge Coulomb island.” Thus, a top Coulomb island 36-12generates a top Coulomb force and is attracted to an edge Coulomb island36-14 that generates an edge Coulomb force and the contacts 36-13 aremade. The substrate 36-4 is held to the substrate 36-5 by the lower pairof Coulomb islands 36-19 and 36-21 and the upper pair (not labeled) tomake the upper contact. The substrate 36-3 has the connection 36-11 tosend signals between adjacent substrates in the stack. The dotted ovalregion 36-10 indicates that the trace on this level may have made anorthogonal turn.

FIG. 37 a-c reveals how daughter substrates become grand daughtersubstrates by using edge and surface Coulomb forces. A system 37-1consists of a mother substrate 37-2 with two daughter substrates 37-3and 37-4. Each of the daughter substrates can comprise one or moreindividual substrates. For instance, the substrate 37-3 contains 9individual substrates while the substrate 37-4 contains three. Thesubstrates 37-3 and 37-4 may utilize both surface and edge Coulombislands. The individual substrates in the daughter substrate 37-3 areheld together by edge Coulomb forces; the daughter substrate moves onthe surface of the mother substrate by using surface Coulomb forces ofat least one of the individual substrates. This is evident by observingthat the movement of the daughter substrate 37-3 in the direction 37-5requires that the moving substrate remain cohesive; the edge Coulombforces provide this function. However, the substrate 37-3 can releasethe edge Coulomb forces and move each of the individual substratesseparately and then reassemble them at the destination. This would beuseful when the surface of the mother substrate is crowded with manysubstrates and only narrow passageways exist that are slightly largerthan an individual substrate.

FIG. 37 b illustrates a “corner substrate” 37-6 can be placed on theopposite surface of the mother substrate to increase the effectiveheight of the edge. As the daughter substrate 37-3 is being moved in thedirection 37-5, the substrate 37-4 is moved until it overhangs the edgeof the mother substrate 37-2. When the center of mass of the substrate37-4 passes beyond the edge of the mother substrate 37-2, the edgeCoulomb forces of the mother substrate 37-2 in combination with the edgeCoulomb forces of tire corner substrate 37-6 and the bottom surfaceCoulomb forces of the substrate 37-4 attract the two substratestogether. Meanwhile the bottom surface Coulomb forces of the substrate37-4 juxtaposed to the top surface of the mother substrate 37-2 repeleach other. This causes the substrate 37-4 to rotate (see arrow)clockwise around the edge of the mother substrate 37-2. After the flip,the surface of the substrate 37-4 is parallel to the edge of the mothersubstrate 37-2. The edge Coulomb forces of the mother substrate 37-2 incombination with the edge Coulomb forces of the corner substrate 37-6help hold the bottom surface Coulomb forces of the substrate 37-4 inplace. Then, as shown in FIG. 37 b, the daughter substrate 37-3 ispositioned with one of its edges lined up with the edge of the mothersubstrate 37-2 and the bottom of the substrate 37-4. Now, the substrate37-4 is rotated counterclockwise (see arrow) until the substrate 37-4 ison the top surface of the daughter substrate 37-3 and becomes a granddaughter substrate. The top surface Coulomb forces of the daughtersubstrate 37-3 and the bottom surface Coulomb forces of the granddaughter substrate 37-4 are used to hold the two substrates together.This process of stacking the substrates can be continued until thestructure given in FIG. 37 d is created. Note that the structure can bedeconstructed (reduced to individual substrates) in the reverse order.

In addition, more corner substrate can be stacked on the first cornersubstrate 37-6 to provide a wider edge. These corner substrates provideseveral features: 1) the area of the edge of the mother substrate isincreased allowing more Coulomb islands to help stop and hold thesubstrate that was rotated; 2) vertical movement of the rotatedsubstrate is improved since there are more Coulomb islands to createmore Coulomb forces; 3) additional metallic contacts can becomeavailable to power up the rotated substrate; and 4) the corner substratecan move laterally to tilt the angle of the rotated substrate 37-4 awayfrom 90°.

The stacking of the substrates of making daughter substrates into granddaughter substrates then great grand daughter substrates can continuefor many levels. FIG. 37 d illustrates a stacked substrate 37-7 whichcontains a daughter substrate 37-8 (the mother substrate not shown), thegranddaughter substrate 37-9 and the great granddaughter substrates37-10. Surface Coulomb forces between the upper two substrates are usedto levitate the upper substrate 37-10 in the direction 37-11. FIG. 37 eshows a separation 37-12. The separation will depend on the technologyof the substrate (CMOS, SOI [Silicon on Insulator], etc.), if waferbonding was used, on the area of the levitated substrate and if thewafer has special processing carried out on them to reduce or eliminatethe foundation portion to reduce the mass. Here the surface Coulombforces are used between the substrates 37-9 and 37-10 to create theseparation 37-12. FIG. 37 f presents the system 37-7 when the daughtersubstrate 37-8 and the grand daughter substrate 37-9 are repelled fromeach other using surface Coulomb forces. The separation 37-13 isindicated. This is an interesting system in that the 37-10 substrate islevitated a separation 37-12 over the 37-9 substrate by using Coulombforces between this first set of substrates. Then, the levitation of the37-9 substrate over the 37-8 substrate causes a separation 37-13 that iscaused by Coulomb forces between this second set of substrates. Sincethe 37-9 substrate is common to both the first and second set ofsubstrates, the surface Coulomb forces between the second set ofsubstrates must also support the gravitation force of the all substratesabove it. The gravitation force of the multi-stacked substrates systemwill require large voltage magnitudes and large power dissipations toachieve large separations.

The stacked substrate 38-1 is illustrated in FIG. 38 a which consists offour layers of substrates (if these were on a mother substrate then thenumber of layers would be five), however, as shown; the mother substrate38-6 is on the first layer consisting of several individual substratesheld together by edge Coulomb forces; the daughter substrate is on thesecond layer 38-5; the grand daughter substrate 38-4 is on the thirdlayer; and the great grand daughter substrates 38-2 and 38-3 are on thefourth layer. As indicated in FIG. 38 b, the substrates 38-2 and 38-3are repositioned using Coulomb forces near the opening 38-7 which existson the three lower layers. Then these two substrates move into positions(not shown but described earlier) to prepare being rotated in thedirection of the arrows into the opening 38-7. FIG. 38 c illustrates thetwo substrates 38-2 and 38-3 now called “beam substrates” inside theopening 38-7. The beam substrates 38-2 and 38-3 use surface coulombforces to rotate around the corner of the opening 38-7. The beamsubstrates can also have edge coulomb forces. With both beam substratesin place the grand daughter substrate 38-4 is levitated and raisedupwards 38-8 using three sets of forces: 1) the surface to surfaceforces between the grand daughter substrate 38-4 and the daughtersubstrate 38-5; 2) the edge forces of the grand daughter substrate 38-4and the surface forces of the beam substrates; and 3) the edge forces ofthe grand daughter substrate 38-4 and the edge forces of the beamsubstrates. Only two beam substrates are shown to simplify the diagrambut additional ones can be used to increase the lifting ability. FIG. 38d illustrates the separation 38-9 which now can be increased by usingthe beam substrates as compared to the distance 37-12 given in FIG. 37e. This occurs because the beam substrates are perpendicular to theremaining substrates. In addition, the beam structures have the abilityto carry signals between the separated substrates. FIG. 38 e illustratesthe daughter substrate 38-5 being raised with a separation 38-11. Thebeam substrates 38-2 and 38-3 are identified. Again

A dense package or stacked substrate such as that shown in 38-1 can beassembled into a structure as shown in FIG. 38 e or another complexstructure under the control of a FSM (Finite State Machine). By way ofexample only three aligned substrates and two beam substrates were used,but any number may have been used. The CAD (Computer Aided Design) toolswill be required to offer the full flexibility of this self assemblytechnique. The CAD tool provides instructions that can be stored inmemory. The instructions can be stored in memory (non-volatile) and theFSM and memory can be inside the stacked substrate. The structureillustrated in FIG. 38 e for example can be further changed in real timeto adapt to changing conditions. The substrates 38-4 through 38-6 areidentical to simply the discussion. Note that the substrate 38-4consists of eight substrates that are held together by edge Coulombforces and are identically shaped. However, these eight substrates caneach have a different area. In that case, a substrate like 38-4 can havea variety of different areas. However, the stacked substrates would notnecessarily be aligned on all edges as indicated in FIG. 38 a. Inaddition, the beam substrates can also be assembled on the outside edgesof the stacked substrates wherever the edges do line up.

FIG. 38 f illustrates the antenna given in FIG. 35 b with a granddaughter substrate levitated over the daughter antenna substrate. Thegrand daughter substrates are 38-13 through 38-17 which could be patchantennas fabricated using SOI or some other very low loss substrate. Thedaughter substrates 35-3 through 35-8 could be ground planes which areseparated by the distance 38-19 and can be adjusted by using the beamsubstrates. Not illustrated are the beam substrates that can be used totransfer the signals received/sent to the patch antenna; this has beendone to simply the diagram. The ground planes can have a larger areathan the patch antenna. Several variations of this design are possible:each pair of the daughter substrates 35-3 and 35-4 can be combined intoone ground plane and the two patch antennas 38-14 and 38-13 can sit on alarger ground plane; and the ground plane can hold additional antennasubstrates so that the dipole can be reconfigured using Coulomb forceswhile in the orthogonal position.

FIG. 39 a depicts a substrate stack 39-1 where each layer of the stackhas an inductor 39-2 through 39-4 inside the substrate. The middlesubstrate 39-6 is placed in between top 39-5 and bottom 39-7 substrate.The distances 39-9 and 39-10 indicate the relative position of themiddle substrate to the two other substrates. The top view of themetallic substrate 39-8 that forms pail of the middle substrate 39-6 isshown in FIG. 39 b. The I/O connection 39-15 is the metallic contactthat coupled to the adjoining metallic substrate. The Coulomb islands39-11 are used to create the edge Coulomb forces used to hold themetallic substrates together. Of course, multiple metallic contacts andCoulomb islands can be formed but are not indicated to simplify thediagram. The side view of FIG. 39 b as indicated by the arrow 39-12 andpresented in FIG. 39 c. The metallic substrate is formed by a back toback connection holding two substrates. The component portion 2-4 a and2-4 b contains the metallic traces 39-13 inside the substrate. Fourlevels of metal are used in this example, but more or less metal levelscan be used. Coulomb islands 39-14 are indicated in the 2-4 b portion. Atechnology (for example, SOI) that can minimize the loss would bebeneficial in this case. Furthermore, the thickness of the foundationportion 2-2 can be reduced to help reduce the loss and mass. Inaddition, the placement of the Coulomb islands 39-14 should be decreasednear the metal trace forming the inductor to further reduce the losses.These metallic substrates can also be used for the antenna substratesthat were mentioned earlier. The I/O connection 39-15 is also shown.FIG. 39 d indicates a series coupling of the inductors 39-2 through 39-4that were shown in FIG. 39 a forming a cylindrical inductor while FIG.39 e indicates a possible transformer circuit configuration where theupper two inductors 39-2 and 39-3 have a mutual coupling of M₁ and thelower two inductors 39-3 and 39-4 have a mutual coupling of M₂. Thedistances 39-9 and 39-10 can be changed by using Coulomb forces to movethe middle substrate 39-6 in the vertical direction to change thedistances and therefore the mutual inductance of the transformer. Manyother inductor/transformer circuits can be created.

Finally, it is understood that the above description are onlyillustrative of the principle of the current invention. It is understoodthat the various embodiments of the invention, although different, arenot mutually exclusive. In accordance with these principles, thoseskilled in the art may devise numerous modifications without departingfrom the spirit and scope of the invention. For example, the individualsubstrates held together by edge Coulomb forces may be comprisedsubstrates using various materials fabricated in a variety oftechnologies. Also, the Coulomb forces can hold substrates together evenafter the power supply has been disconnected from the system. Thisoccurs if the islands are the non-volatile type since these islands canhold the charge indefinitely and therefore can maintain the forceindefinitely. The connect substrate can also be used as a low impedanceswitch when connected and offering an infinite impedance when theconnect substrate is detached. The devices and circuits of amanufacturing technology can also be incorporated into all of thesubstrates (for example, the corner, connect, and beam substrates)although this may have not been indicated in the drawings forsimplification. The various shapes of the metallic antenna on substratesfor antenna formation may be, but not limited to, circular, hexagonal,stripe, rectangular or polygonal shaped. The inventive aspects that areused in the antenna formation are applicable to other system designsusing other substrates. The antenna can also be designed for lowercarrier frequencies than 75 GHz since Electrically Small Antenna (ESA)can be designed. Other examples of antenna, but not an exhaustive list,include omni directional and circular polarized antennas. The inductorshave been shown using only one turn and the same metal level; however,the inductors can be multi-turns and can have portions of the metallayers on different levels to avid crossovers and crossunders in themetal layers. The invention can be practiced using the CMOS, MOS,BiCMOS, SOI, MCM, MEMS or BJT technology. The materials to form devicescan be silicon, plastic, GaAs, SiGe and SiN.

APPENDIX TO EXAMINER

The published paper “Fundamental Limitations of Small Antennas”,Proceedings of the IRE, 1947, pg. 1479-1484, by Wheeler, providesinformation if the dimensions of the antenna are much less than thewavelength.

In a published paper, “Computation Methods for Design and Control ofMEMS Micromanipulator Arrays”, Computing in Science and Eng.,January-March 1997, (Vol. 4, No. 1), pp. 17-29, Bohringer et al. In pp.20, right col., 1^(st) para., “The other side of the actuator consistsof a denser grid above an aluminum electrode. If a voltage is appliedbetween silicon substrate and electrode, the dense grid above theelectrode is pulled downward by the resulting electrostatic force.Simultaneously the other side of the device (with the tips) is deflectedout of the plane by several μm. Hence an object can be lifted and pushedsideways by the actuator.” The actuator is a level with a fulcrum.Bohringer uses the lever to move a substrate on the surface of thearray. An electrostatic force pulls on one end of the lever while theother end of the lever moves upwards and physically makes contact withthe bottom of the substrate (see FIG. 7). The friction of the physicalcontact movement of the lever is transferred to the substrate and movesthe substrate across the surface. Also, see FIG. 14 which uses theactuator array to move and rotate silicon chips. Our invention does notrequire friction to perform the movement, it avoids friction.

In a published paper, “Microassembly Technologies for MEMS”, Proc. SPIEMicromaching and Microfabrication. Santa Clara, Calif. Sep. 21-22, 1998by Cohn et al., show a process flow for dry electrostatic self-assemblyin FIG. 9. The flow process is also shown in U.S. Pat. No. 5,355,577issued Oct. 18, 1994 to Cohn. The trap voltage is applied to a singlebottom plate of a base and the blocks are applied. The electric fieldfrom the bottom plate induces a charge into the blocks attracting them.The system is vibrated until the blocks stochastically move into theirpositions. Once in position, the blocks are solidly attached to the baseby a metal deposition. Our invention, among many other things,incorporates adjustable charge plates into the blocks giving them theability to be independently controlled to generate controlled forcesthat can systematically assemble and furthermore re-assemble orreconfigure a system.

In a published paper, “Novel Electrostatic Repulsive Forces in MEMSApplications by Nonvolatile Charge Injection”, The 15^(th) IEEE Int.Conf. MEMS, 2002, pg. 598-601, by Liu et al. They propose in the lowerleft column of pp. 598 “using nonvolatile charge injection to realizeeffective electrostatic repulsion force actuation. The MEMS structuresare integrated with Electrically Erasable Programmable Read Only Memory(EEPROM) cells and are connected with the floating gate of the EEPROMs.”In addition, in the last paragraph in the lower left column of pp. 599follows: “The devices for electrostatic repulsion force demonstrateconsist of pairs of a parallel beams of various lengths (160-400 mm)with 1.6 mm (design rule minimum) gap. The beams are anchored at bothends by oxide. Each beam connects to the floating gate of an EEPROM cellfor charge injection and monitoring.” One of the co-authors holds U.S.Pat. No. 6,597,048 issued Jul. 22, 2003 to Kan which describes in theirabstract: “A method of injecting electrostatic charges into opposingelements of MEMS structures to produce repulsing forces between theelements.” The entire structure or opposing elements are formed andremains attached to the one substrate for both reference. Our invention,among many other things: incorporates Coulomb islands in juxtaposedsubstrates that are used to control an independent movement of detachedlevitated substrates; and proposes a plurality of EEPROMs connected to acharged structure where one EEPROM can charge the structure negativelywhile the second EEPROM can charge the structure positively.

In a published paper, “Survey of sticking effects for micro partshandling”, Intelligent Robots and Systems 95, Proc. 1995 IEEE/RSJ Inter,Conf. Aug. 5-9, 1995, pp. 212-217 by R. Fearing offers an insightfullook into the sticking effect or stiction of micro components.

U.S. Pat. No. 4,947,228 issued Aug. 7, 1990 to Gabara describes a singlevia contact through the entire substrate to the back surface of thesubstrate. U.S. Pat. No. 5,298,800 issued Mar. 29, 1994 to Dunlop et.al. describes a closed loop link adjusting the intensity of light in afiber. U.S. Pat. No. 5,396,195 issued Mar. 7, 1995 to Gabara describes aLC CMOS tank circuit. U.S. Pat. No. 5,708,389 issued Jan. 13, 1998 toGabara describes a circuit for transferring digital data through acapacitive interconnect. Both U.S. Pat. No. 6,281,590 issued Aug. 28,2001 and U.S. Pat. No. 6,465,336 issued Oct. 15, 2002 to Gabara et. al.describe the use of an MCM with traces to bypass the input and outputcircuitry between two substrates and make a permanent connection. Pleasesee FIG. 29 b of this specification. The traces are located in the granddaughter substrate 29-9 and the substrate is levitated into position byColomb forces to make a temporary connection. The “connect substrate”can then be detached and used to provide a metallic path between twodifferent daughter substrates as a metallic switch for antennas, forexample.

A system for electrostatic bonding is described in U.S. Pat. No.6,638,627 issued Oct. 28, 2003 to Potter. Charges are placed into afirst region of a first unit at least adjacent to a first region of asecond unit. A bond between these regions is formed between the boundcharge of the first unit and the induced charge of the second unit. Asecond U.S. Pat. No. 6,841,917 issued Jan. 11, 2005 to Potter as statedin the abstract, describes “an electrostatic interaction system includesa first structure having a first fixed electrostatic charge and a secondstructure having a second fixed electrostatic charge. The polarity ofthe first and second fixed electrostatic charges determines a positionalrelationship of the first structure to the second structure.” Ourinvention, among many other things: forms pockets of islands in twosubstrates where each island can be adjusted independently of eachanother allowing lateral motion, detachment, attachment, rotation, etc.

A proof mass is caused to levitate by electrostatic repulsion and isdescribed in U.S. Pat. No. 7,225,674 issued Jun. 5, 2007 to Clark. InCol. 8, line 35-39, “In addition, if both the side electrodes/proof massand the stabilizing electrodes are charged to the same potential, thereis no danger of short-circuiting, in contrast to floating devices basedupon the attraction of opposite charges.” Clark uses a charged proofmass that is non-insulated. The oxide surrounding this proof mass is asacrificial layer. During the MEMS processing step of releasing theproof mass, the sacrificial oxide layer is etched away thereby exposingthe proof mass. The exposed proof mass can now make electrical contactwith the stabilizing electrode and short out. Interestingly, the proofmass is charged up initially by this connection. For example, see Col.5, lines 28-36. “One convenient method for charging the conductorsinvolves the application of a voltage to conductors 3 and 7, therebydelivering charge to conductor 5 in contact therewith. However, whencharged, conductor 5 will repel from both 3 and 7 to float as depictedin FIG. 1b. Thus, conductor 5 remains in electrical contact withconductor 3 for so long as is necessary for conductor 5 to accumulatesufficient charge to repel or “float” and break electrical contact withconductors 3.” Once the electrical contact is broken the conductor 5levitates. Our invention, among many other things: forms a plurality ofislands in the levitated substrate where each island can be adjustedindependently of each another allowing the same structure to be placedin motion, attachment, rotation, detachment, motion, etc.

U.S. Pat. No. 7,250,826 issued Jul. 31, 2007 and U.S. Appl. 20070176704published Aug. 2, 2007 to Gabara describes a way of reducing the eddycurrent loss within a coil or inductor by placing a plurality of coilsin parallel.

U.S. Appl. 2007018739 published Jan. 25, 2007 to Gabara describes amechanical lifting of an inductor in of a structure to decrease the eddycurrent loss in the substrate. Please see FIG. 15 a of thisspecification. The substrate 15-2 containing the inductor has beenlifted away the mother substrate 15-3 using Coulomb forces. In addition,material has been etched away from the far side of the inductor tofurther cut on eddy current losses in the substrate.

U.S. Appl. 20060122504 published Jul. 8, 2006 to Gabara et. al. describea charged capacitor that is used to power a independent unit. Once thecapacitor is placed in the system, it remains stationary for the life ofthe system. Please see FIG. 29 c of this specification. The substrate29-26 contains a capacitor 29-27 that is charged when the system 29-24is in contact with the mother substrate and discharges when thesubstrate 29-24 is detached from the mother substrate. The chargedcapacitor can be detached from the substrate 29-25 and moved to anotherdaughter substrate to provide additional power to a second substrate.

U.S. Appl. 20040080456 published Apr. 29, 2004 to Tran describes “aselectable antenna array formed from a planar field ofmicroelectro-mechanical switches (MEMSs)” in paragraph 2. Paragraph 12provides: “The switch is fabricated using silicon nitride as thearmature structural layer and silicon dioxide as a sacrificial layersupporting the armature during fabrication”. All MEMSs devices arepermanently anchored into position once the array is fabricated. Thismeans that the freedom to provide a feedpoint anywhere on the array islimited. In paragraph 73, Tran indicates that “Theoretically, there areno limitations to the shape of the active element. Practically, theshape is limited to the placement of feedpoints, . . . .” In paragraph75, Tran reinforces this limitation again, “Practically, the position ofthe active elements is limited to the position of the feedpoint 202, orselectively engageable feedpoints in the field 101.” Our invention,among many other things: allows a conductive path to be formed from theRF front end to the feedpoint by positioning antenna substrates on themother substrate to where the feedpoint is located.

1. An apparatus comprising: a mother substrate with a plurality of firstCoulomb islands: a daughter substrate with a plurality of second Coulombislands; and a control unit that can adjust a charge of the first orsecond Coulomb islands to levitate the daughter substrate into anequilibrium position with respect to the mother substrate.
 2. Theapparatus of claim 1, further comprising: a plurality of Coulomb forcesgenerated between the plurality of first Coulomb islands and theplurality of second Coulomb islands.
 3. The apparatus of claim 2,whereby the plurality of Coulomb forces can move the daughter substratewith respect to the mother substrate.
 4. The apparatus of claim 1,further comprising: a plurality of capacitors formed between thedaughter and mother substrate; whereby the control unit monitors valuesof the capacitors.
 5. The apparatus of claim 4, whereby the control unituses the values of the capacitors as feedback information to maintainthe daughter substrate in the equilibrium position.
 6. The apparatus ofclaim 4, whereby a displacement of the daughter substrate causes avariation in the values of the capacitors.
 7. The apparatus of claim 6,whereby the variation in the values of the capacitors is used by thecontrol unit to estimate the magnitude and direction of either theacceleration or deceleration of the daughter substrate.
 8. An apparatuscomprising: a plurality of air bags; an accelerometer generatescapacitance information; a processing unit analyzes the capacitanceinformation to calculate a direction and magnitude of a deceleration;and the processing unit determines an optimal number of air bagsrequired to minimize an impact of a crash and enables the optimal numberof air bags.
 9. The apparatus of claim 8, further comprising: one ormore of daughter substrates; whereby the accelerometer is formed bylevitating at least one daughter substrate over a mother substrate. 10.The apparatus of claim 9, whereby Coulomb forces are used to levitatethe daughter substrate.
 11. The apparatus of claim 9, whereby thecapacitance information is extracted from capacitors formed between themother substrate and at least one daughter substrate
 12. The apparatusof claim 11, whereby the processing unit calculates the direction of thedeceleration from the capacitance information and generates digitalinformation.
 13. The apparatus of claim 8, whereby the processing unitapplies the digital information to a bus coupled to the plurality ofairbags.
 14. The apparatus of claim 13, whereby the digital informationenables the optimal number of air bags.
 15. A method of calculating thedisplacement of the daughter substrate, comprising the steps of: placinga mother and a levitating daughter substrate into an equilibriumposition; monitoring values of a plurality of capacitances formedbetween the mother and the levitating daughter substrate; identifying achange in the value of the capacitances; and calculating thedisplacement of the daughter substrate from the change in the value ofthe capacitances.
 16. The method of claim 15, further comprising thesteps of: determining the direction and magnitude of the decelerationfrom the displacement of the daughter substrate.
 17. The method of claim15, whereby the capacitances are arranged to measure a lateraldisplacement and an orthogonal displacement of the daughter substrate.18. The method of claim 15, whereby the capacitances are arranged tomeasure a vertical displacement of the daughter substrate.
 19. Themethod of claim 15, whereby at least one Coulomb force is used tolevitate the daughter substrate.
 20. The method of claim 19, whereby theCoulomb force is generated between at least one pair of Coulomb islands.